Again I think he was introduced (created) into the Marvel Universe with the WWH storyline in mind. They had hoped to create a character that people would have some affection for so when the Hulk actually kills a hero (and if #110 showed anything they set up the premise that the Hulk has always been able to avoid casualties-- so this'd be massive for his psyche) people would react to it. Unfortunately what they didn't count on was that people not only don't have an affection for the character, but they have the reverse-- a total dislike for him.
Sentry was actually created in 2000...I really doubt the World War Hulk storyline was anything they had in mind at that time, as I do doubt that their purpose for the Sentry was just to be taken out by someone like the Hulk. But you are entitled to your opinion!
It is true that Sentry is a Superman,Captain Marvel,Miracleman,etc. rip-off... I mean most superheroes are ripping off any previous characters (and/or powers) that were created before them anyways. But you also have to think of it in terms of the Marvel Universe...in which most superheroes (like Spidey, the Hulk, the X-Men and Mutants in general) have a bad image in the public and media eye and that is in contrast to the DC Universe where most of their superheroes are worshipped and loved. Marvel Universe is grittier and between them and DC's universe, Marvel's is more grounded in reality.
So with that sense, Sentry was tossed in as a rarity in the Marvel Universe...a superhero who was loved by the public, the media and the superhero community. Of course, Marvel built a whole story about him being an undiscovered creation of Stan Lee's (which was just marketing hype and they revealed was bogus) and introduced him into the Marvel Universe as a superhero that was universally "forgotten" by the whole world because of his fear of his enemy: "The Void"...which turned out to be the Sentry himself.
Anyways, I for one like the Sentry and I find him interesting...and perhaps you're right DarthNeil about fans not liking him, because Marvel hasn't really thrown him around the place like they do with Wolverine and DC does with Superman. Nevertheless, he has brought on a lot of attention from fans who want to see him go toe-to-toe with the likes of the Hulk, Thor, Galactus, etc.
And I also think his "re-introduction" in New Avengers where he tears Carnage in half in space is one bad-@$$ intro.