Things games should have, but don't

[Shadowth117]

Um, fighting games are WAY more complicated than Halo.

Yeah, but that's not my argument. The engine itself is more complicated, though saying that about the gameplay of an FPS would obviously be laughable as you pointed out. Like Koopaul said, a lots going on in the environment at once. There's realtime physics for almost every object and there can be a lot of those on screen at once which have to be monitored by every player's console at once. The players themselves as well as the vehicles have to be accounted for this way as well with just as much if not more precision at once so that if someone shoots anything in particular at once you're getting an accurate collision report. As you well know from playing a lot of fighting games, collision is extremely important to the gameplay since if that screws up than it screws up everything.

In most shooters, the players also have many more options to move around than in the average fighter where your movement is generally restricted to a plane with the occasional game allowing you to move about in it a 3d area a little bit. Even then you don't have to deal with the players interacting with other obstacles such as if a player runs behind a wall to get cover or if you choose to shoot out of a small crack or slit in a wall. Yeah I'm probably forgetting a lot of things about fighting games as well as shooters that play into this as well, but hopefully you at least somewhat get my point.

Edit: Not to mention that lag can potentially ruin a fight just as much in a shooter as it can in a fighting game. Missing even a single headshot can completely screw you against anyone who actually knows what they're doing in the game.