It would be interesting to see the files split into bigger categories, for example, how the add-on board structure works on the forums here. From there, players can filter from specific categories, or view all at once. That would ease up on the eye-sore of a million icons.
It would also be nice to see if something like this could collaborate, or at least, include add-ons that have been submitted to RTB and now Blockland Glass. If there's any incentive to use this website, it's going to have to include a wide range of add-ons, and make them very easily accessible. It's a valid point that having this and Glass completely separate almost completely nullifies this seeing as how Blockland Glass has had fair progress.. this isn't some sort of monopoly where having one choice is "unfair to users due to lack of choice" because it's literally just splitting content.
In short: If you can find a way to merge add-ons submitted to Blockland Glass, the forums, and what's on the RTB archives, this would be the perfect website to bookmark and frequent and submit to for add-ons.