You're starting with the assumption that a site needs a hierarchy...
But there is a hierarchy. Some people here can modify the web site code, and I can't. Some can moderate others' posts, and some can't. Some can altogether reap others' posts, and some can't.
... that certain users need to be trusted with power over their fellow users. This theory is faulty, we can write software which works in a more egalitarian way.
Oh, come on. How long have you been lurking the internet? this dream keeps coming back again and again since 1994, and the sad truth still is that you must groom community sites. Countless tried again and again, and after reaching some critical mass there simply is no way around building fences to contain the dirt.
I have already perfected the theorem of how such a system works, and I will provide proof of concept in the fullness of time.
Good luck with that. What is the chance that you are actually this genius to succeed where countless others from Usenet to Slashdot to Reddit to Digg have failed?