Mostly its an unprofessional wad of code written by some PhD's. It went through some hands and ended up at Google, who mercifully refactored it somewhat and renamed it.

I've been dealing with the code base for 5 years, and never liked it. Had to rewrite the APIs every time we got a new source version, to fit our model which isn't the 'conference call' model. I'd be glad to see something more app-agnostic that just dealt with negotiating P2P streams, without so many assumptions about what/why/when the streams are.