I think the atmosphere of MUSHing has changed in the sense that you need to be proactive in your search for RP. Like a few people said, putting on the RP request board that you're looking for RP doesn't really get as much of a response anymore as offering up some kind of scene idea, for example.
I also see people have way more success when they are sitting in a public space with an RP flag on (as long as they make it known that they have a public scene open). Ares makes that a little easier with you being able to tag a scene "open", and then you give a shout out on RP Request or whatever channel going "hey I started a scene at the diner, come on down if you want RP".