Would it be a big deal to add spectator mode into the servers, like modern games have? where you watch the game from other another player's view and have to click a button to switch to another player/join the game.
This is quite a useful feature if you're planning to host tournaments within your community and stream them with live ingame footage.
Just a thought, haven't seen it implemented in any other Steam port so far, some have spectator but you'll have a hard time following people around since it's just a view you have to move yourself all the time.
Once again, a feature modern FPS have, the ability to level up. Leveling up has no ingame advantages, but you could for example implement new character layouts to the game (new colors and such). Will give people an incentive to actually use the Doomsday engine before some other port.
Same thing as before, I haven't actually seen any source port do that this far.
I might post more ideas on the forum when they get in my mind, I really like the way the Doomsday Engine feels and looks
Feel free to share you thoughts/ideas about this