Of the more recent 4* character releases, who is the best?

I went through all those with P4nther/Shuri/Main Event, and that team was out of control. And my panther is lvl 94 5/4/4. I've also been using Shuri as a general purpose Coupon with a stealth battery component. Everybody is enhanced by having their powers cost 3AP less, particularly when enemy powers cost 3AP more. Plus, if you are only using her red, matching 3 (or more) fortified tiles means they are accruing double AP and doing double damage. Those two characters have such obvious synergy (like Hobofist/C4ge) that it is easy to assume they only like playing with each other, but Shuri in particular is a force multiplier on all kinds of teams.