I remember the old quakeworld (qw) days where I played mostly tdm(team deathmatch) and some ca(clan arena). I personally think that tdm sucks for soldat and would require a lot of work to make it good but clan arena would be easy to set up and I think it would be a load of fun.
If your not familiar with ca, both teams spawn simultaneously and the last team to have a player still alive wins. You usually play best of 5 or something like that.
Simple but never got old in qw.
As for now I'll stick to soldat ctf.