I think the problem with Unreal 2 is that the game was just average. It didn't really break any new ground (from what I'd heard) unlike Unreal. It didn't distant itself enough from other FPSes, so in the end so it got a rather lukewarm reception and didn't make a big splash.
Gamerankings has the score for Unreal 2 at 79%, so it didn't do amazingly well when it went for review.
Gamerankings has the score for Unreal 2 at 79%, so it didn't do amazingly well when it went for review.

