As much as I love SS2 and think it's better than Bioshock, I can't say it's shooting mechanics are better. It's strengths are found in everything but gunplay. Maybe next year it will move higher up, since the game finally got a re-release.
The HL2 hate is odd. That game has gotten damn near every award possible for it's campaign. I don't think it's the best HL game (Opp For), but it's campaign is better than most of the COD knockoffs that plague shooters nowadays.
The list isn't that bad. If anything, it highlights how far the genre has fallen since even PS2 era, and that's not even counting the PC.
Next time vote.