I've tried allying with Mr. House, Yes Man, NCR, and the Legion. I even tried allying with Benny, but he always gets wasted by the Legion in the end. We need more than 4 possible outcomes.

I haven't tried the wild wasteland perk. Is that worth it?

Wild Wasteland is a funny perk and adds some new content and references. Unfortunately all work has stopped for New Vegas, so no more official updates.

It's not likely that New Vegas will see any more updates since Skyrim is out.

Wild Wasteland perk only replaces a few events with strange/comical events. Such as the gang of grannies. Not really worth it unless you don't mind having a slightly more tongue-in-cheek wasteland experience.

Besides, there's not many ways you can go aside form the four endings. But if you perform (or neglect) sidequests, you get more variations.