The concepts of them are very unique - I think where a wrench gets thrown in is when some folks (myself definitely included lol) would forget/ignore the fact that the more you do, the more you're viewed as a "threat" and therefore an easy target for elimination. And I remember I tried to have my cake and eat it too, I liked the socialization of the he said/she said in the alliances, but then I also tried to do too much in the challenges. That is a recipe for disaster in those games.
I'd be down for another though I think one tweak that would make it work real well is smaller challenges (similar to that on Survivor). Similar to the old SA Bar Crawl type challenges that last 2-4 days, that don't require a lot of effort, and can lead to quicker eliminations and a lot more socialization!