That's a great idea. I was thinking about how to keep all happy/excited emails from the customers publicly available.
Angry/sad emails go straight to the bug tracker.
We just wanted to control the growth before we got all the bugs ironed out. We didn't know how well our servers would scale, and we don't have a support staff. Not having the plugins listed certainly does impact the distribution and the exposure of the product in terms of volume - when we come out of closed beta, we'll have them there.
One of the big advantages, though, is that we also get to have more self selecting and passionate users this way and they tell others who would care.