It's good the filters are being done too, and I know the horrible search is an old relic that was always slated for reworking.

I hope, feebly, that the person doing search is at least talking to the person doing filters, since search/browse really is what most of the AO3 is all about and it all should be integrated into the design of the site from the bottom up and they aren't two discrete things.

But users will see things in a way coders can't because they don't know or care about code structure. It's a shame their ideas were never asked for. Unsurprising, but sad.