You're basically asking them to be consultants...I don't think they'd be too thrilled to get into the consulting business.
1. They are already doing it for the YC funded firms. 2. Unlike real consultants, they can build startups, fund startups, get involved more. 3. YC has lot of traction for this, I feel a good idea is being overlooked.
1. It's more time consuming than you think
2. Doing it for YC funded firms make sense because they have vested interest. This is different than being bombarded with a ton of questions much like a support forum, for which their time is probably better spent on YC as a whole.