"In shooters" isn't specific enough, because I'd say there's more to it than just the perspective, there's how the game elements use the perspective. For example, Gears of War makes extensive use of special cover stances that involve doing things like firing over your shoulder, so a first person perspective just wouldn't work. However, the Thief series is all about what Garret can see and intimate maneuvers (leaning just enough to see around that corner without being spotted) would make it impossible to play in first person.