Basically you want UT2k4 again Shlomo
If I was to have a hold on the UT franchise, I'd definitely add more of a social side, as has already been suggested. However, on the topic of unlocks;
I would say UT unlocks would have to be approached differently than other games (i.e. where you start with nothing and have to work your way up, adding things to make you better). If I were to do a UT unlocks system, I'd have maybe three categories of unlocks, Defense, Offense, and Wildcard. When you start you can get things like extra 50 health, 25 points of shield (defense), your start weapon be a shock rifle or bio rifle instead of enforcer (offense), or a wildcard (randomly get berserker powerup after a multi kill). At any time, a player can only play a major perk (say, an offense perk where you start with a sniper rifle), and a minor perk (in the same category, a minor perk would be boosted enforcer damage or quicker hammer recharge time, or slightly increased wall jump distance).
By the same token, each perk may or may not come with a disadvantage. Most all major perks would come with one - like for instance, if you picked to have a shock rifle as a starting weapon, non combo damage is reduced and you might have a lowered max health with health packs (but would still be able to increase to 100+ via health vials), or they might have a random chance - like for instance if you choose to have extra health, your enforcers might do more damage for head or crotch shots.
This way, perks don't give you an advantage so much as they tweak the game to your play style, while still giving you accomplishments. An in-game leaderboard that you see, say, when youre waiting to load a server (instead of that freaking useless chat screen), let's you see the top 100 players in the entire game vs. your standing. This would encourage people to actively try to get on that board, because every person who plays the game would see them every time. A tighter clan integration system (more so than just a tag at the front of your name), like an integrated clan challenging system and maybe even a persistant warfare map for each server. I'm thinking like you have a big map with different control points. Each control point = a match. Every time one team wins the control point, they take it over and advance closer towards the enemy's main core. When you reach the enemy's core on the main map, you fight a regular battle on the battlefield, and if you win, you win the meta-war and the game is reset. The most similar to this I guess would be Return to Castle Wolfenstein: Enemy Territory, or Freespace 2's SquadWar, where individual matches were calculated into a larger persistent whole.
Notice that I DON'T want to turn UT into an MMO. I'm just suggesting this because a sense of accomplishment is what really drives players to the whole achievements thing, or the unlocks thing - they want to feel that what they're playing is accomplishing something. Nothing in UT matters - you lose a match or win it, big deal, the next match is from scratch, so to speak. A server by server constant battle would encourage server loyalty, community building, etc.
Whew, I'm done. Anyone want to make a mod and submit it to MSUC?