Bollwerk Ruins 2, and BioHazard-LE have been added to my personal favs list. Both are great fun to play IMO.
Bollwerk is a rather well done remake. It has some imperfections in bot pathing, but it's the 1st version of this map I've liked. I heard there is a secret in here, but I stopped reading at that point, as I wish to find it myself. Still haven't.
BioHazard is tough to figure out at first maybe, and got some funky colors, but still, I like it. It's fun to pay. And both would work fine in 4-on-4 or 5-on-5 matches.
Swartz is redoing his classic McSwartz, hopefully it will turn out as well as these. (Bollwerk is a remake, not sure about BioHazard) McSwarts is a very old map, possibly as old as Q1, and it's been done several times at least.
Saw a remake of Hydro16 that
could have been pretty good. But the 'ceiling' is like 10ft high outside, and I can grapple all the way across the sky.

Ah well, perhaps another version will come along. I always liked that one.
Gonna start putting links on those as well, just in case anyone is ever browsing and get's interested.
And I'm still undecided about Sharpfish Park. What do you think? (Same link as Festive Ridge.)