Disclaimer: I will be using terminology for only Empire sided classes. So no sentinels or vanguards will be mentioned here
Gameplay: Personally, I would change the juggernauts new ravage ability the old one before patch 5.0. But only for the Rage and Immortal specializations. As in the Rage rotation, there is enough of a delay for where this ability will be used to do more damage, adding much more in gameplay. Also do this for the Fury and or Annihilation specialization for marauder. And get rid of the "hew" ability from vengeance, as it is a turn off for me as the animation feels too slow.
Another would have to be to give back the flamethrower ability to bounty hunters, if not, at least just to Powertech. As that felt like a such bounty hunter thing to do, using your flamethrower mounted onto your wrists. But if you were to do this, make it so that it will apply a small dot onto each target affected. Instead of spreading all of your applied dots. Just to give it more of a balanced compared to that new one which replaced it.
Hehe, now, we all know how much of a bad spot sorcerers are in atm. With them being the squishiest class in the game (dps specifically).
So why not (for the dps versions only) give their quick resurgence ability a buff? As that ability specifically is one way in which they can endure against those other ranged classes for at least a little bit longer (besides using unnatural preservation).
Another MAJOR idea I have is to, depending on your force alignment, change in which animation your abilities are. Because I personally love the Guardians animations compared with the juggernauts ones. So having this will still allow me to play and talk to with the friends and guildmates I have come across. Yet still retain the advantage of essentially being able to become a "jedi" when I am a Sith. Though there will have to be some changes, such as you can turns this option off in the characterization screen, possibly underneath outfits? Also, you will have to Fully commit to one side before these changes would happen. So for instance, I will start out as a assassin and retain all the base assassin animations that they have at this current moment in time. But if I were to become light side 5? All of my abilities will instead change into that of a shadow's animation at this current moment in time. All of the abiliites will stay in the exact same position, but instead have a different animation when activated. Because I don't think a lightside sith would still use their force lightning As I said before, since this is only for cosmetic changes, this should be an option and can be turned off.
I am no elitist expert into any of these ideas, and do not know the complications or functions this can have. Just some ideas spouted out their, because personally, I really would like to see at least some of these implemented in the future. <3