Split screen makes no sense and would be used practically never. It's also a problem in terms of graphical performance and networking issues, not to mention source doesn't support multiple controllers being hooked in at the same time (as far as I know). There is only a concept of 1 local player.
The radar in the mod is a direct replacement for "screen looking" since the radar is extremely informative and precise, yet it doesn't afford the player with direct knowledge of spatial location which keeps things tactical.