sentinel needs to be nerfed, end of story.
seriously, when i play my sentinel i'm always amazed at how easy it is to completely wreck people. if you dont do that while playing sent you are not doing it right.
remove the healing debuff, its not needed anymore.
nerf the god-mode cd or remove it all together. the 30 sec dmg reduction is already good enough.
when the only counter to a class is to stun them or run away you know something is wrong.