Well, I would say don't remake any of the old levels - but I think I agree with Bart that some of the original Dark Forces SP maps would make some interesting conversions to MP - with some redesign.
As for the rest, I'd like to see...
1. A ship-to-ship boarding level in space - which could fit nicely into a CTF context. It could be Empire vs Rebel over secret plans, or two pirate teams out to steal each other's loot.
2. An underwater city/installation level - maybe Otoh Gunga revisited?
3. A level with lots of ice - maybe an assault-type level re-enacting part of the battle of Hoth. And I mean slippery
4. Maybe...just maybe...a Sulon farmstead level, with Kyle's team trying to take back his old home, while a Tusken team defends. It could even be done in a CTF context if Kyle's team had a large enough ship as a base, parked not too far away. If the farmstead team wins they keep the ship, if the ship team wins, they keep the farm.