In a recent message on p5p he wrote that a three month release schedules means not enough releases, and too many releases.

In the beginning, three months is too long. But later on in the traject, not enough happens in three months to make a release. Releasing .x x months after a .(x-1) release may work better.

But that still doesn't solve the problem of many people asking for features/bug fixes, etc, and only a very few people doing the work.