Pvt Shlag has a point on the Left 4 Dead / Left 4 Dead 2 issue, but I don't think a programming requirement is realistic, when we can simply add something to the drop down.
If any rules are made, it should apply to all mods and not any one specific mod, otherwise were going to have so many sets of rules it going to be a royal pain to keep straight what I need to do to get something approved. The initial rules by Bailopan seem fine. FZero and berni have good points so not much more I can add, just wanted to state my thoughts.