People who DIDN"T want split screen? A perfect FPS for me would support all aspects of FPSing. Multiplayer local, online, vehicles and bots if you can help it.
If TCon 1 had 4 player Split Screen, it would certainly fare better IMO.
Take a look at past FPS legends, Perfect Dark N64, GoldenEye, Halo(s), TimeSplitters and to be fair CoD HD versions. And StarWars Battlefront 2(xbox) was a real winner as it was vehicles, Bots and multiplayer galore. Ok it's 3rd person but you can switch to FPS on it.