Dooku is still very good, as a leader, and a counter to Jedi.. The characters that have seen the strongest boost are ST Han, Daka, and of course RG. Rey, GS, and QGJ are still beasts. QGJ did get a damage nerf, but his dispel got a Psuedo buff in that matches last longer and you have more opportunity to use it.
Replies
Royal Guard
Savage
Fives
Kylo Ren
Rey is still a Beast
Qgj is still decent
GS still good
Nerfed means the game makers (in this case EA) made a change to the game that made a specific character less powerful.
Toon is just an easier way to say "character" without having to say/type the entire word.