I'm pretty sure I met a guy in-game who said that he played (almost exclusively saberist) with his left hand using a controller (joystick instead of WASD) and his right hand using a mouse for aiming. Or maybe it was the other way around, WASD for movement, joystick for aiming? I think it was the first way.
Anyway I don't remember his name at all so this post is virtually fucking useless to you. Unless anyone needed inspiration for actually viable ways to use controllers. Cuz that guy was really good as a saberist, iirc.
I'm super dubious of it being useful at all for gunners though, because they need a lot of buttons on-hand to switch guns quickly and stuff. And for it to be viable for heavy force users, your mouse better have a lot of buttons on it.
Also I know that on one of the computer's I've played on (but not the other), I can turn on the joystick settings that are in options, and use a joystick to control my aiming. And by "a joystick" I actually mean "this weird analog paddle on the side of my mouse that my computer rationalizes as a joystick."
Certainly one way to get it sort-of working would be to use Joy2Key, but you wouldn't get any analog functionality like that.
edit: slightly bizarrely, looking at the intended in-game functionality, it's built so that moving the joystick forward or backwards moves you forward or backwards, while moving the stick left or right rotates you. So your joystick movement is limited to, like, KOTOR movement. Rotate and advance, no strafing.
edit2: Despite how the functionality is described, how it ACTUALLY works is that the joystick is used for aimng (with the Y-Axis inverted). And how I got my gamepad joystick working in Windows (10) was: I brought up the Game Controllers settings, hit "Advanced," and was presented with a question of "Select the device you want to use with older programs." Which I answered, letting me use my XBox 360 with MB2.
But the right thumbstick isn't understood as a thumbstick. The X-axis is ignored, and the Y-axis is read as buttons. The left thumbstick is used as an airplane-style inverted aiming joystick, unless you check "X/Y-axis as buttons" in which case it's basically literally joy2key, and you can map it to WASD movement if you want.
I messed with it for a while and I think left-hand-360-controller right-hand-mouse is basically viable if your mouse has a ton of buttons and you ONLY play gunner or ONLY play saberist. You can't play both, because there simply are not enough buttons in-hand to map all the force powers AND all the guns you want to have instant access to.
edit3: this messing around has made me really curious about the viability of the Steam Controller for this though, since the Steam Controller has more buttons and has mode shifting. Hell, I wonder if I could make a bunch of different class configs on the Steam Controller instead of in-game. I need to buy a SC and mess around with it.