Playing devil's advocate here (because I quite like the idea of the new system), surely this could lead to a situation where a writer can do 5-6 critiques on various people's work, and then not get any back, as everyone's critiqued the same pieces for their 1-2 crits required to post a song - therefore potentially resulting in some users getting masses of critiques but only doing one crit themselves, whereas another could do 5-6 critiques but not get a thing.
Eh, I'm sleepy.