The thing is that you need 1) Sentry, a 3* character that brings very little to the team besides his green and self-damage, 2) a character that accelerates green because his power is way too expensive and 3) one character that takes advantage of those countdowns. Why bother when you could use three 4*s, one of which puts down countdown tiles (Coulson, Antman, etc.) and TWO characters that benefit from countdowns expiring?
4* Carol and Sentry IS an absurd combo, though, if it goes off. Also doesn’t help that Sentry covers are pretty hard to come by these days.
Just discovered the medusa, carol, and carnage combo…where has this been my whole life.
I really do love the new dynamic of these characters and makes trying out various combos incredibly exciting.