Suggestion for Sentry rework.
Sentry is supposed to have the power of a million exploding suns but he is greatly lacking. How about reworking his signature ability to have a chance to start the fight with different buffs, regen, fury, physical/energy resistance, etc., with a small chance of starting with a high level of all of them. In the comics, Sentry's mental state greatly effects how strong he is and when he's stable and in control he's practically a god. You can keep him as is and just add the chance for different buffs, hell you can even remove the chance at indestructible.
He's fun to use and a great character but he just really doesn't have much of a place in end game content and that should change.