Surprising that Pace didn't get in, but for me, Marvin Harrison is obviously the biggest snub. Clearly, his not getting in for the 2nd time is a result of his connection to the shootings after his career, for which I'm still confused why he hasn't been charged. 3rd all time in receptions, 5th in receiving touchdowns, 7th in yards. Still has the record for most receptions in a season (143) and about 20+ other records. Doesn't get to be more clear cut than that.
I'm also surprised that the all time leading scorer in NFL history still hasn't made it. In case folks don't know, that's Morten Anderson and his 2,500+ career points. I think it's very questionable if another kicker ever gets in, until maybe AV gets his chance. Kickers and punters are players, and deserve the recognition, IMO. The 5-10x a game they are on the field can result in some of the biggest moments of each game, and I think as the years go on, it's becoming more and more evident just how important the kicking game is to a team's success.
Warner not getting in doesn't surprise me at all. Outside of those three big seasons with St. Louis, he really was not a very good NFL QB. In fact, if you look at those seasons, only 1 was really amazing. He's kind of like Terrell Davis (who also didn't get in again) in that sense. Few great years, and a SB win (or two in TD's case), but not enough longevity to get into the HOF, IMO.