Meh. As part of the two-person club that liked the Sentry, I respectfully disagree:
part of the fun of the character was that you never knew what he was going to do next. Like a crazy uncle blows in every family reunion with a new girlfriend or something. It was cool from a reader's perspective to see how he behaved around people, and how he didn't really know how to behave at all: like human emotion was totally beyond him; you know, maybe he was human, or used to be, but his powers elevated him so far beyond that. Like Galen/Galactus, maybe, only a little more unhinged.
I thought that was a neat concept and a little Franklin Richardsy too: take an immensely powerful superhero idiom and give it to someone who's not ready, developmentally or otherwise. It seemed a good commentary on any/every messed up Marvel superhero there is: you're superpowerful, who knows just how powerful exactly, and you can save the world pretty much without a thought, and you find you still don't have your shit together; you're not the role model type, you're not Reed Richards or Cap, these leader-types, even though you desperately long to be; your mind is still a mess and so you deal with that while dealing with the usual retardations of a superhero life.
So much so in fact that Norman freakin Osborn becomes his voice of reason. I think that's where Sentry really shined. As someone who maybe didn't belong to the MU--maybe he could have been suited to a cosmic story ("Marvel Two-In-One: Drax and the Sentry stop the General in the Negative Zone, and Annihilus too!").
That kind of weird cosmic juju maybe could have made him a little cooler, but probably at the expense of warped psychology--which Bendis took and fully exploited. Which is fine. I think the overall point of the Sentry is that we didn't know what to make of him, and he didn't know what to make of the world he lived in. The kind of world where idiots like Norman Osborn and Loki have the power and Captain America and Iron Man are in hiding. I mean, that's a weird-ass world. And the Sentry existed to show that a little. Even fi his opportunities were squandered.Like in Young Avengers where, faced with Kree and Skrull kill-squads on either side of the Avengers, ready to kill Hulkling, Cap has Bob fly a wounded Patriot...to the hospital.
Anyway. I liked reading about old Bob Reynolds and his nutjob ways. I confess to hoping he comes back someday...