As a player who plays everything, or I could say I "mained" every class for at least 3-6 months already, here's my opinion on current gunner vs jedi.
My general feelings about playing jedi: comfortable, can be successful while being totally brainless and without making any effort
My general feelings about playing gunner: requires you to make effort (mostly because of aiming), takes much more discipline and thought to succeed
However the matchup is as close to being balanced as it can be imo. 2 entirely different classes will never be "balanced". Jedi has regenerating (infinite) resources, meanwhile gunners don't, jedi is melee class, gunners are mainly range class. So with two entirely different skill-set and playstyle just what can you call balance? If both side can win with 50% chance? Well I don't know about the exact chances, but you can win on both sides easily, mainly because a big part of the fight is the rock-paper-scissor like mind game of run/walk vs push/swing, so if you guess well you are likely to win both as a jedi and a gunner. And I think the issue of this thread is that gunners aren't guaranteed to win if the jedi makes a bad push, but if the jedi makes a good push, he's almost guaranteed to win.
That's why I say gunner needs to make effort, cause it's not enough to withstand a push with walk, you need to make it count with good shooting and even then you have to follow up well to secure your win, and sometimes you have to accept that you can't chase down the jedi, that depends on many factors, the most important thing is where the fight takes place. Generally multi-level areas favor jedi heavily, I mean where the jedi can use 10-40 fp to jump up to a place where the gunner can't follow and open areas with 0 cover favor gunners (there's no corner or cover which the jedi can use to regen fp even for a second).
Now the fight can go thousands of ways and I could get lost in many details, but I'd like to focus on the most crucial thing, aiming. From my experience a big factor how the matchup will feel to you is how much the gunner can hit the jedi/sith. Basically if the gunner's not hitting the jedi then ye the jedi will be able to make 2-3 bad swings, a bad push but then still win the fight. However when the gunner has a good hit rate, then it can often feel like the jedi can't do anything. He has a death timer on his head, if he makes a swing or push, he'll just die sooner, the only option is to retreat (while he can) and wait for a better opportunity (in lets say a multiple vs multiple situation). So my statistical experience is that if your aim is on point, then 1-2 bad push/swing is enough to get the kill. Getting a good aim sucks though, especially to do so consistently in this game. My personal experience is that sometimes I can get a headache and my hitrate is still poor, but sometimes I'm not even trying and I'm hitting almost everything. For example in my best moments I kill a jedi with only p1 by flinching 4 swings in a row, but sometimes I won't even flinch the 1st swing.
Now you don't need to be an aimgod to succeed and land all your shots. Aiming at the right time can be enough to win. To illustrate, imagine these 2 scenarios, both of them happen like every day in the game.
Scenario 1
Jedi is at mid-long range closing in on you. You're shooting pretty well (let's say with e-11), by the time the jedi reaches you, he's down to 40-50 fp, but when he makes the swing, you fail to shoot well in that moment and lose.
Scenario 2
Same situation but you're shooting terribly, jedi gets in swing range with 90-100 fp. He makes the swing and in that moment you shoot him perfectly in the head with a few shots and win.
Discipline: as a gunner it will happen with you in almost every round, that a jedi reaches swing range on you. At this point it's very easy to get confused/mentally totally shut down (and thus your aim reduces to 0) while you're deciding between holding walk or trying to run cause you don't know whether the jedi will do a yolo push or a swing, and more importantly WHEN he will do it. To combat this doubt, you need discipline and mental composure to keep your aim up while you decide whether you're gonna run or not. This situation from a jedi perspective is much more relaxed, depending on how many FP you managed to close the distance with. If I'm practically at full FP then I can just wait for a good opportunity, feel out the movement pattern of the gunner, most weapons can't drain FP that quickly and also assuming I managed to close the distance with full FP, the gunner is most likely unable to drain me, so I can just wait until they run out of ammo. Many gunner just give up and go for a melee fly kick, which is easy to deal with too (in this case, you only need to hurry if there are other enemies you have to worry about). If I'm at 30-60 FP and the gunner keeps firing at me quite well then I actually feel like I'm forced to take action, but it's still a relaxed situation, depending on the area, it may still be very easy to retreat.
"Brainless" jedi: So as a jedi you can often win with a strategy that you set your mind on before the battle. For example when you reach a certain distance, you're gonna do a push cause the gunner might just start running. If it pays off, you won without thinking or putting in any effort. Other popular approaches: jump swing, jump push, double pull, pull+swing, swing spam, and keep mixing up these options round after round depending on the result. These can all work and require way less mental effort to do than aiming in this game. Now you can decide on pushing based on the movement of the gunner, but you don't have to, and you risk getting baited by the gunner.
I believe the more brainless you can play as a jedi the better your chances. If you're too rational you can be read like a book and a good gunner has easier time aiming at you.
Jedi is also comfortable, cause you don't have to worry about things that you should worry as a gunner. Entering a door with 0 information. Let's say you find 3 gunners and a jedi in push range. This sucks if you're a gunner, you can immediately die with push+shots, or you might manage to escape but that's not very likely. As a sith you can flee easily, you eat some shots which only took some fp, which regens back. Not to mention, as jedi you can scout the next room/corridor with sense, which again makes the game much easier. So gunner has to take precaution and think more about trivial actions like opening a door or going around a corner than a jedi has to.
Choosing the setting/place of a fight: I've said a few things about this earlier, but now I'll focus a little more on it, as it's also really important and impacts the matchup greatly. Some examples. As jedi, having a cover next to you is very useful, like a box. You throw out a push, then hide behind the box, this way only prefires can damage you. Very cheap, very effective, requires good effort from the gunner to deal with it. As gunner, you should try to position yourself before the engagement so that the jedi won't be able to have advantages like this (if possible). Other thing to look out for is try not to have a wall behind you (you have to look out for this even during the fight, as it depends on the jedi's position too), it reduces your evasive options and also you won't gain any distance from a bad push. In my experience if both players are ignorant to factors like this, then usually the fight will go down in a place, where the jedi has some kind of advantage. Also I have to add, that gunners often can't escape a disadvantageous situation which jedi can and have to accept to fight in it, but even a slight difference in position in a room can have a big impact.
Distraction: making distractions is also much easier to do as jedi, you can very easily troll clueless enemies and feed them to your teammates. An example I have in my mind: I jumped over the enemies in dotf main/hangar and took 4 jedi for a tour in the hangar. They blindly followed me and they didn't care that by following me their back ended up being exposed to my sniper teammates. So I saw my snipers shoot them down from the main/hangar door one by one. What's really funny is that even after 2 died the remaining 2 still followed me. Btw I also paid attention to move in a straight line without changing directions, so they followed me with a straight line too which easy to aim at. Point is, pulling shit like this is very easy with jedi/sith (effortless, doesn't require much thought) and if you try to do similiar distraction with gunners, there's a good chance you're gonna get raped by the distracted opponents even if your team benefits from your distraction unless you planned it out really well.
Overall it's a tough topic, I see complaints from both sides in game, and I can often sympathize with both sides' complaints to a degree as I play evertyhing. But on the forums there are always exaggerated complaints. I remember a few years back there were complaints on the forums that gunners "only have to spam shots". And now there are some exaggerated complaints too, like a knock down doesn't matter on jedi, cause they can just quick rise (sorry if I didn't quote it properly).
I feel like jedi have easier time, but if the gunner puts in the work and you can't bullshit him with random push/pulls, then jedi feels very limited and useless. I wouldn't change much about the current system, after 1.4 I'm pretty satisfied with 1.5. I really disliked 1.4's hold block forever jedi, in 1.5 it became better.
The thing is that many gunners are clueless about fightning jedi, and those who can deal with jedi well are often obstructed by their clueless teammates (block their fireline, block their movement etc.), so you can pretty much always have an easy time with jedi if you're an experienced player. I think of jedi almost the same way as I think about deka. Very good to bully a weak team, but can't do anything to a good team on it's own because of it's regenerating resources which tries to be "balanced" for both 1v1 and 1vMultiple.
Also in win team it's very easy to use jedi, if you have problem just retreat/hold block for a few seconds, you'll be backed up by your teammates. However as a gunner in win team, you will still pay the price for screwing up.
One more thing, is that it's bad to talk about gunners generally. SBD, deka, wook (godcaster or fury makes many difference too) have a really different match up vs jedi/sith. BH and hero with their high speed plays very differently too. Dex 3 ARC, tricksters like nade whores are an entirely different story. So as a clarification I mainly talked about ETs with e-11/a280/t-21, soldiers, clones vs jedi/sith in this post, and to some degree it's true for bh, hero, arc without dex 3 and mando.
Different guns make a difference. I could talk alot about the imbalances between guns, why I think M5 is one of the best weapon to fight sith right now, or how p3 got messed up with 1.4's block forever meta, but that's another topic. Or how good dlt's burst fire became after the 2 shot speed increases (now burst is one of the things with what you only need 1 mistake (bad swing/push) from the jedi to win hahaha). But since this post is already a long mess, I'll just end it for now.
EDIT: also the best tip, which you can read in the game too. If you have trouble dealing with something, use it yourself. So just play jedi if you can't handle them as a gunner.