Age of Republic is definitely the most balanced and even then it's kinda meh. Grievous is one of the best PvE Villan/Hero in the game and Dooku is amazing at controlling enemy heroes and dueling.
Yes, but mainly for Galactic Supremacy, and Starfighter Assault sometimes. Disclaimer, though, everyone has max-level star cards. Expect to suffer for dozens of hours, if you're trying to max out all classes. The matchmaking will inevitably pair you with or against high-tier star card players. Mostly because veterans are all that's left, but I digress. Oh, and to circle back for a minute, when I said _"all classes",_ I meant *_all classes._* There's no universal level, and you can't fully upgrade your star cards until class rank 30, meaning you'll have to rank up 120 times across all 4 classes. Pain personified. Especially when you earn the same amount of credits per match --- performance and time played don't impact end-match rewards --- so you'll have to suffer through the tedium of getting destroyed in basic outfits. Two more caveats worth noting, there's no proximity chat, or even squad chat, so I suggest playing this game with friends. Otherwise, you're in for a pretty lonely, boring experience. Secondly, many of the top players tend to hog heros and villains, even going as far as to camp them in the character select menu, so I suggest getting used to being a powerless grunt.