His point is that there must have been some way for Bungie to specify that Slayer Pro is Spartans only, for example, therefore it seems odd that they didn't just include it as a gametype option so people wouldn't have to go through the hassle of finding the right gametype as a basis to work from. Also, what if you want to create an Elites only objective gametype? You're screwed, that's what.
I made a thread about ideas for Halo Reach: http://www.forgehub.com/forum/halo-reach-discussion/109831-post-all-your-ideas-here.html
Splatters Only. The fact that turning damage to 0% made this effect in Halo 3 makes me even more annoyed that it doesn't work in Reach.