Sorry for being annoying about this feature, but without some sort of URL redirection, the vast majority of servers will never run custom maps. Most players just don’t like to download from websites (having to look up the maps and finding the exact version, etc.) and/or download from the server. Most admins will turn off server downloads of maps and/or mods because it eats up bandwidth and/or lags the server.
It’s very tragic that Quake 3 didn’t have this. There are so many wonderful custom maps out there, yet most were never actually used on servers due to the problems mentioned.
URL redirection - in Doom 3 - would truly fix this issue, so custom maps and mods can be fully utilized. Otherwise, most will just sit at map sites with very few players trying them out.
Thank you for considering this.