I'd place Ico in there for the way it turned a video-game into an atmospheric and emotional experience. Also, Valkyria Chronicles for giving a TPS feel to an SRPG. Tomb Raider for basically popularizing TPP. Resident Evil for obvious reasons.
Anyway, the deeper into any media we go, the less 'revolutionary' content we will have. There is only so much that can be done in any medium. Eventually you hit a wall were improvements are more about quality and producing variations. If there is anything revolutionary, it will probably come from an indie game, which will then be incorporated into larger scale games (which will probably get the credit). That's really what happened in the past, with most revolutionary game-play coming from games we've never heard of, which was then perfected by studios with larger budgets. For example, people talk about Gears of War instead of Kill Switch when they talk about TPP cover shooters.
Rather than revolutionary, I'm really hoping Fallout 4 evolves the FPS RPG. That would be my biggest wish. Oh, and Half Life 4 coming along and blowing us all away in terms of FPS scope.
