Calling anything op in open mb2 is a bit ridiculous. Depends on what you consider op though...
-They can fly. Easy getaways for jedis and gunners.
That's a benefit for sure, but why would it be op. Others pointed out jedi can push you down when you try to fly etc. I won't say more about this
They have a one shot sniper rifle with 2 shots that reloads half the time as a proj rifle.
It's a controversial topic, but if you wanna call mando op, then probably this is the reason to go with haha. Add to it that you can quickly switch between rifle mode and sniper mode, which gives the benefit that you can switch between playing as a sprayer or a sniper in split seconds.
"-That sniper rifle can also be an insanely high damage weapon. It's balanced though."
You say it's balanced when it's a reason for why mando is op according to you?!
"-2nd/3rd highest health/armor not including dekas/SBD's as they both have huge handicaps for their health. 1st is Wookie. 2nd is ARC."
I'll get into this in deatils below, but their health/armor is only better than hero, bh amongst the 1 lifer class, not counting jedi/sith but they can be practically immortal with their fp/bp.
-They have a unblockable flame thrower that can kill jedi very quickly and makes it very tough to get close.
Others addressed this too, and I'd say using flame thrower is only needed against a passive jedi, who's blocking all day, if they just run straight up to you, you're better off shooting them with ee3 and drain their fp. Also I never see top tier mandos using flame thrower, they just annihilate you with ee3.
"-Most of all, even after they run out of ammo, health, armor, flame thrower and jetpack fuel, they can just blow themselves up in an easy way to get a free kill.
It could be argued that it's unfair or cheap, but well they have it. But you know, you can cheap them too with most of your class, alt frag nade and then pew pew well, if you think you won't be able shoot him down after alt frag, then just infinite them with backthrow katas, clones can blob them down. Jedi has push, hero has dash, arc has dive roll, wook can tank it, also slap/barge may be an option too if he does it really close. Every reb class has a way to deal with it, but generally just keep the distance, but most importantly never facehug a mando with rocket, let other teammates fight him and let them deal with the rocket. Last resort, shoot the rocket down and let it blow in his face. Yea it's very advanced tactic, success rate is quite low, but it's definitely a possibility, practice increases your odds, can be done accidently too. And one more, in the case which you said where you shot the mando 9 times and he's low hp, just stay calm and deliver the last shot before he can launch the rocket, preventing a low hp mando from rocketing is quite easy if you anticipate it, problem is that you're not so you start to panic and unable to give that finishing blow.
Now mando is my least played class, so I'll not really talk about that, I'll just preach about what is op etc, cause every year we have multiple threads that a certain class is op, needs nerf, we had hero is op, clone is op, wook is op, deka is op, p3 is op (hero/bh is op?) on the forums just in the last 2 years if I remember correctly. How can it be that every class gets called op in this game? Cause if you played this for a few years, you'll see every class called op at least once, it's just a habit here.
Imo an op class would have high durability, high damage and effortless way to deal its damage and can easily beat every other class. You can find good op classes in FA, for example the hazardtrooper in um_prisonraid. AOE gun (easy to land) with good damage, also has str 3 with wook slap, 200/200 health with regen armor if i remember correctly, he lacks speed at least, but still 90% of the rebs classes just gets crushed by it, and like 2-3 classes have any real chance to kill it. As the hazardtrooper you can just fuck around, not even fight back, let them shoot you for a while and then you can still easily kill them. That's the definition of op for me.
Now for the open classes: only SBD, deka, jedi/sith have any real durability, (jedi/sith is a very special case),these classes can take on more lightsaber slashes and take several shots without dieing. For deka and jedi it's because they're the only classes with regenerating resources. SBD is just that tanky and cannot be headshotted.
Wook comes close after that cause they can take 2 yellow slashes and several body shots, but wooks can go down really fast with headshots, so I consider them much less annoying than an SBD. Here I'd mention that probably the only op thing in mb2 is getting in consecutive headshots, and well it doesn't happen too often. The average hit rate in this game is horrible, newbs have like 10% hit rate regular players 40-60%, 80-100% only happens for brief moments. Main reasons high movement speed, especially high strafe speed, slower bullet speeds, spray. Well you can get better hit rate with low rate of fire weapons like sniper and pistol. Like a good proj user will hit 7/7 sometimes, depends on his targets too, cause this game is as much about dodging as much it is about aiming. But the point is when somehow you keep getting hit and if it's in the head, then you go down very fast very easily with soldier, ET, clone, bh, hero, ARC, mando doesn't matter which you use. Soldier, ET dies faster naturally.
To further emphasize headshots value, any weapon with 100% hit rate on the head (which is mostly theoritical) will look like a beast, even p1 will look very strong, and making difference between e-11, cr2/cr3, a280, t-21, m5, ee3, p3, bowcaster, sbd blaster etc. is basically impossible, they will all look very strong, killing every gunner (except deka, sbd) in 1-2 seconds. Now you can find players for each weapon, that will claim that it's op or that it's the best. And if the weapon is op then so is the class apparently. And frankly all of these weapons can look the best on a public server, as I said on average the hit rate is horrible, so if you can harness the potential of any weapon in the game better than the masses, you'll look like a beast and others will say your weapon is op.
Overall every gunner has the potential to deal high damage, landing the shots is hard with every class (some weapon is easier to aim than another), and we have 2 gunner classes with extraordinary durability. Overall I think deka, SBD could be considered op imo, cause they can kill you fast with a few shots but you can't kill them with a few shots. Dekas and wooks have situational opness, where they're invincible in some match up. Like 400 hp fury wook goes after a soldier/ET/bh. Or soldier tries to fight a 200/700 deka.
With all that said, one weapon may be stronger than the other if we were to examine it in stupid theoritical ways. Like let's say both gunner hit with every shot in the head and then we find out that ee3 triumphs over e-11 secondary, cause ee3 kills hero (100/60) with 3 headshots, meanwhile e-11 kills mando (100/100) with 5 headshots, but actually the fight is a draw, cause e-11 has higher rate of fire and the hero managed to shoot out the 5th bolt just before he got hit in the head by the 3rd bullet of the ee3, and since our hero has perfect aim and the mando cannot dodge, that bullet will hit the mando and he will die 0,45 seconds later than our hero. Draw your conclusions. Now as ridicolous as it sounds, I think the bullet numbers required to kill are something like that if all of them hit the head, but in reality many shots are missing or they hit shoulders/neck/upper chest. All I know is once I rekt a 100/75 mando with 3 pistol 1 shots in a row with pistol soldier, I know it cause he complained that he had full hp and was like WTF, only reason he could die cause all those p1 shots hit the head. And btw that mando didn't suck, he managed to kill all 3 of my lives in another round, cause in reality it all comes down to you, your opponent in that particular time, hit and don't get hit if you want to win.
Edit: I'd also like to know why ARCs aren't as powerful. Mandos are basically ARC's but the ARC sniper does like a third of the mandos sniper. ARC's also can't fly and get 2 items which sith just push away. (rockets/pulse grenades)
I'm much more comfortable with ARC than with mando, really depends on how much experience you have with each class probably, I played ARC lot more than mando. I think dex 3, stamina 3 M5 arc annihilates sith this build, you don't even really need a good hit rate with it cause the fp drain is really good on it. Just get in a burst of 3-5 bullets on a running sith, that will make them a sitting duck/jumping rabbit until they slowly run out of fp. Or if they continue running, then keep hitting him (easier said than done I know) they run out of fp quickly. Sprint and well timed jumps help you outmaneuver any slash that may come your way. Only need to be little wary of knock downs, but even that can be solved with flinch. I find it funny Helix mentioned lightning sith, if they use lightning, that means you can sprint freely for 3 or 5 seconds, but I guess many arcs still walk after they're hit with lightning, but sprint > sith speed. Add in some rolls, lightning sith should never catch you unless he gives up with lightning and goes for push ofc. Pull is the most troublesome for dex 3 arc imo, but even then flinch can still save the day. I'd say it's easier for ARC to fight sith than for mando to fight jedi, cause ARC can just outrun the saber swing, if mando can't jetpack for some reason, he has to rely on flinch often, doesn't seem to be much problem for boss mandos though. But fp drain seems to be even better for ee3.
In gunner match ups mandos seem stronger than ARC, to put it shortly.
EDIT: I didn't even vote in the poll, cause there's no exact nerf proposed in the original post. My answer for that depends on what kind of nerf do you want. EE3? What kind of ee3 nerf? EE3 is a beast in the hands of mando masters for sure. Does it need to be nerfed? I don't know, everyone can decide for themselves, I just wasted my time here instead of doing real work.