Extend was about as good as it got in balance, not to say that it didn't have issues, but with the exception of Tager match ups, it was pretty solid.
My vote sir, is no. Just hell no. We are about to have 3 or 4 cloned (story wise) characters of the same chick (Noel, Lambda, Nu, and Mu) who isn't even in the game yet (Saya).
Logic? Nah
+R was pretty balanced. It was AC that had the issues with Testament and Eddie (0 bad matchups? Really?)
You are right though, CP isn't insanely imbalanced (ala MvC) but there is more of a defined low tier than there was in Extend for damn sure.
HOWEVER
A larger cast is not exactly a good thing. We're getting to the point where it is actually getting to be a bit much. More matcups, less overall balance. Tager, Tsubaki, and Makoto somehow got WORSE, and we still have issues with Bullet, Izayoi, Amane, Kagura, etc. It's become much easier to determine who's lower on the totem pole and who's higher, and to me that spells trouble. I'm just saying.