FWIW - we had 100% capability of doing ragdolls in U2XMP.
We didn't do them for exactly the reasons that Captain Kewl has stated. We originally intended to fling them out of a vehicle when it exploded, but to be honest, we had four people working on the entire game at the time, and a little visual gimmick wasn't so important to us as real gameplay, so it never made it in.
There are a ton of gameplay implecations if you try to do ragdoll deaths that would need to be dealt with.
First and foremost, they're done client side, so you'd have to switch that over to being server side to prevent all sorts of horrible exploits in addition to a lot of visual glitches that would occur even if people weren't actively trying to exploit. A few obvious things fall out of this (sync between server and client, additional server load, etc.)
Second is that anyplace a ragdoll falls, they have to be revivable in that position. This is easy when we've got an animation of their death, because the body isn't interacting with the environment. It becomes much more difficult when you want the body to -look- like it's interacting with the environment, but not get stuck someplace where badness happens should the person get revived. Under a railing, smashed in a rock, etc. etc.
Third is that there is a good immediate indicator that someone hasn't tapped out - and that is that they continue to animate on the ground, writhing, awaiting revival. Once ragdolled, UT2K4 characters aren't going to take animations. So there's no visual indicator between a guy awaiting revival and a dead guy.
Fourth is that it's a matter of degrees. Once you see guys ragdoll and gib from certain types of deaths, why can't you just make them do that to them while they're lying on the ground? We wanted the ranger to have his special mercy kill ability rather than everyone just shooting a downed enemy until they gibbed or died.
So, just so everyone knows - these were all factors into our concious decision to omit ragdolls. It wasn't a technology limitation at all, but there were enough issues that would require resolving that it simply died amidst trade-offs to make other parts of the -gameplay- better.
Perhaps the guys at Free Monkey will feel strongly enough about this to resolve those issues, but given our loading, it just was a silly thing to be trading off features against.
Were I pursuing it right now, I would probably do the exploding vehicles thing, and perhaps make bodies ragdoll when a player taps out or is mercy killed - basically, all non-revivable, non-gutblow deaths. It's a compromise that avoids all of the problems above, but still gives you some good ragdoll visuals here and there.