On a community playlist:
I might be alone in this here, but I think the best part about the Bungie vs. World playlist was the novelty of it. If you have a permanent playlist of just community made Foundry and Sandbox maps, I feel that the novelty would wear off quick and the maps would get stale.
I do like what they did with the maps on the BvW playlist. Shishka did a quick look through to see if the map wasn't modded or if it wasn't completely broken, and just threw them in a playlist for 24 hours, where not much harm could be done.
I think that making one weekend a month a community map DEXP weekend would probably be the best way to go about it. That way, you'd get a new rotation of maps without the fear of having to be stuck with a completely horrid one for an entire month and the map makers get a lot of feedback to improve their own maps.
If the map is determined to be good enough, then it would eventually be placed into the normal playlist rotations.
I'm sure that its much more complicated than just that, but so far it seemed to work well with BvW, and hopefully we'll get some of the better maps from that into the playlists.