I don't think it works that way. Do you know any example of an existing webpage/event/thing where the people behind it said "it needs to be the same but more fun!", and it actually worked? I find lesswrong to be fun as it is, and I want it to attract people who are attracted to the actual content, rather than some fun-nes sprinkled on top. (I'm not saying lesswrong cant improve, and that I'd necessarily want to conserve it exactly the way it is though.) The reason wikipedia for example is so wildly successful is that it does what it does really well, and that thing is something people want and need. So no, I don't think that would be a good goal :)

(Aware of/sorry for necroposting)