For me, it's because Hill was a nifty college player that just barely got by. He's was a good hustle player, but he was far from a physically dominating one. Sometimes these types of players turn into over-achievers and do much better in the NFL than people expected (Lofa Tatupu, etc). But more typically, they become solid, forgettable contributors that most of the casual fanbase doesn't even notice. I really liked Hill before the 2013 draft- he's similar to ivotuk's favorite- Joe Vellano. They can't get much push and they can be moved in the run game, but they give 110% on every snap and every now and then, they'll slip through the cracks and make a play in the backfield.
Or to put it another way, Hill is a Tim Ruskell type pick. Nice guy, tries hard, low-risk. Though I liked Hill and mentioned him in the same breath as the top DTs back in February at SDB, I was really surprised that it was Seattle who drafted him, especially with some very athletic 3-techs still on the board. But hey, Max Unger was a Tim Ruskell pick, and he's worked out great in the new regime. Brandon Mebane. Earl Thomas had a Tim Ruskell profile. PC/JS have found success even when they acquire players Tim Ruskell would have liked, so I wouldn't hold that against Hill. I'm interested to see how he does. I just think he will, most likely, continue to be a scrapper rather than a massive difference maker.