A feature originating from (I think) the 3D gaming-community. Something that would really aid level-creators and users:
level prefixes!
Some of us already use them and with long-filenames there's actually no excuse. It really helps you organizing your levels. For instance it's much easier to spot which levels are CTF, Battle or Race. If your JJ2-directory is filled with levels, could you remember whether a randomly picked level is a battle- or a CTF-level? Wouldn't it be easier if you just needed to look at the prefix, e.g. "CTF-Carrotus.j2l"? Less hassle cleaning out your directory or picking a level when setting up a multiplayer game.
This idea ain't new, but consider this more a tip or a request. Here are some prefix tips:
CTF - for capture the flag levels, e.g. "CTF-Diamondus.j2l"
TRS - for treasure hunt levels, e.g. "TRS-Caves.j2l"
RC - for race levels, e.g. "RC-Tropical.j2l"
BTL - for battle levels, e.g. "BTL-Tavern.j2l"
and some different playing modes people tend to use:
AS - for assault levels, e.g. "AS-Fortress.j2l"
HOT - for hotel levels, e.g. "HOT-Crap.j2l"
Obviously single-player- and cooperative-levels need no prefix. They'd be the ones without. So, feel like taking on this lil' piece of advice?

Comment, discuss, I'd love to hear!
-haze