Okay, I may be somewhat biased, but honestly, there are a few characters who really need some nerfs and boosts... Because, let's face it, there are some characters that just plain overpowered... And some that are waaay too underpowered. My ideas?
Shino:
Okay... Let's face it. Shino users are able to spam Konchuu Detonation waaay too much... I mean, A total of 5 Chakra for 1 Chakra Drain and 20 Damage? That's a little too strong for a starting character. I'd say increase the Chakra demand on Placing a Konchuu, and either weaken the damage dealt by detonation or increase it's chakra cost so it's less spammable.
Gaara:
Okay. Suna Shuriken does 6 Damage and homing. Understandable. Suna no Muya is also pretty decent. Sabaku Kyuu And Sabaku Sousou, however... Yeah... I'd say either increase Sabaku Kyuu's duration, or decrease Sabaku Sousou's chakra cost. It's near impossible to use them otherwise...
TS Sasuke:
I don't have him, but I've seen what he can do, and Chidori Nagashi is just a bit too spammable in my opinion... Plus, how can it reflect?! It's just a field of electricity, not a shield or armor...
Just some opinions and observations I've made... *Shrug*