Can you imagine how many time you will need to lvl your weapons and characters when the SDK comes out ? ... only the time necesary to create a map with one side caged in a tiny space without weapons or ammo and the AI at the lower lvl .
Killing Floor has similar maps maps only intedted for lvl up or get achievements , lot of games with stats and achievements had this class of servers ... DOD:S , CS:S , TF2 ...