You have hit it with that one statement. The "Assessment for Learning" Intiative from the UK governement has a big focus on P2P assessment. It is at the core of the governement's view on education and at the core of numerous academic studies.
Leaving it out of the core of Moodle is also tantamount to ignoring a fundamental truth, kids learn as much from their peers, and more deeply, as they do from their teachers.
This module has too much to offer to lose it now. Its time has come to grow, not wither. Can I program? No! but I can teach and I know a good idea when I see it.