Yeah Leia isn't too bad particularly in Galactic Assault for objectives. She's about the only hero who can attack enemies while keeping a teammate safe to do the objective and can keep them safe from even explosive damage.
Her down fall is that her bubble stops teammates weapons and enemy light sabers and vanguard shotgun users aren't hindered by the bubble and sometimes are helped.
In hero vs villain situations I prefer more mobility and hard cc over the situational shield. But she can output a lot of damage for a short duration so she does need to be respected.
I like Luke, I think he's one of the better light side heroes for Heroes vs Villains. His card that allows your push more knock back is pretty fun. I launched a Bossk up a ramp and off a cliff yesterday, he looked like Evel Knievel!
As of right now Rey is pretty effective, but honestly she is very easy to play against. Once you get used to mind control you can easily play around the inverted controls.
Her ability that charges forward is also very easy to play around. Just expect her to use it and dodge to the side then punish her as she uselessly goes running into a wall.
I honestly think she will be the weakest of the light saber heroes but she's effective as of right now.