I have boxed crysis, but steam wars, but im not worried either way. Ive yet to have problems making mods work with steam.
And if steam distributed the mod, that would mean HUUGE boosts to player base. I remember when Age of Chivalry came out on steam, there were hundreds of servers and you had to wait in line to get into any of em. And any patches are auto applied by steam! Alot of people gripe about steam but i say its just too damn convienient!