Ultimately, the site didn't solve my problem though, which was to get some reuse out of my lego collections. But that wasn't a shortcoming of your site ... rather, I concluded that Lego has explicitly designed most of their models to be "non-reusable". I.e. even though I have about 10 flagship models (all technic), I don't get 100% completion on any non-trivial set.
As I recall, initially you site didn't have too many MOCs. That might be one way of solving the problem. Consider a gigantic set like the Unimog ... listing a bunch of MOCs made solely from this set would address the problem of reuse.
One more thing ... one of the things I was trying to do using your site was figure out what sets to buy in order to be able to complete the legendary "Motorized Bulldozer" set. Your site says ... if you get X, you'll be 97% complete. if you get Y, you'll be 96.5% complete, etc. That isn't what I wanted to know. Rather, if you said ... buy X and Y to get 100% completion, that would solve my problem. In fact, if you provided options with different combos, that would be even better (due to availability and preferences). E.g. To get to 100%, buy X and Y, or, buy X and W and K, or, ...
Thanks for creating a great resource for the AFOL community! Good luck!