There were a handfull of distinctive characters from UT99 I want to see come back. Besides the ones we know will come back anyway (Malcom, Brock, Lauren, hopefully all humans), I hope Kragoth and Cryss are the main necris again (Brock and Lauren as necris was an oxymoron), and I also want to see Arkon (the shirtless old Rawsteel guy) Blake (the male commando), Anna (the female commando) and Jayce (female Merc). I have to agree tha Olga is pretty cool too. I am disapointed to hear Harlin is returning, because he was always the dorkiest Iron Gaurd guy. I don't remember Johnson or Rylissa.
The skaarj need to come back, they are trademarks of Unreal. I wouldn't mind seeing a hybrid or two either
As far as UT2003 characters, obviously the Juggernauts were the most distinctive, out of that crowd, so they're coming back anyway. The nightmare guys are gone, and even though they were kinda cool, I'm not sure they really fit Unreal anyway...they were more like Quake characters. The Gen Mokai just felt like stand-ins for the skaarj anyway, so I'm not too to see them go. The mercs were not terribly memorable either, though I kinda liked Wraith, Saphire (the UC1 version), and those twin guys. The robots from UT2003 were not terribly memorable either, and Epic will always have more robot designs to pull out of the ass anyway. Plus, the Xan robots were cooler.