Require a piece count
Make it a requirement when post new projects that an approximate piece count be added to the listing so when someone supports the project and is asked to say how much they would pay, we have a better idea of what the cost of a set would be based on the number of pieces
Carter Johnson commented
This is a good idea, but also a bad idea. For people who use software like LDcad and LDD it is very easy to acquire a count, but people who have built amazing things in real life would have to tediously disassemble their builds and then count every piece one by one to get an accurate measure. The only two benefits I can see to this would be the ability to judge price, but it isn't very difficult as-is, and the ability to estimate how long it would take to build the kit. which is also not that much of a problem.