It takes skill and if your lucky, good team work.
Which is rare.
PvPers get tired of playing against the same style enemies, doing the same things, but playing against Humans, if it wasn't for the same maps would be different every time.
It seems for me, while playing against different people who go at the game differently it becomes challenging because people are unpredictable, usually. I just wish they'd add more game types, Capture the Flag, King of the Hill, a Sword of Croat version of Oddball.