There are no excuses for this lapse of quality. The point here is this man, Carmack, was going on and on about huge textures. Nobody has cared about textures since height maps were all the rage, no pun intended. In all seriousness, Doom 3 was a better game. This pile is already in the budget rack at most retailers. UT3 is what we need. Look at Arkam Asylum, Arkam city, and the whole slew of other franchises using this tech from UT3.
Id is a washed up metal band from the 80's that has failed to reinvent itself, lost it's talent at every turn and can no longer play the tune that found the fame before.
FaIL Barn! Failed and finished. 1/2 out of 5 stars for excellent 80's textures.
The engine is optimizied more for consoles with limited speed. I think the target was 60 fps on ps3/xbox. Well for pc this way of programming was so new that amd completely failed with their drivers and still id delayed a 2nd patch because of amd. I dont think that will improve the textures much however (you can apply some filters however) as they are already compressed, maybe you need a 100 gb texture pack for highend cards. At least it was a game that did not require a new card, completely different to bf3 where new cards are needed to play with max settings... Every approach has its pros and cons, but you definitely have got optimize for consoles as the market is much bigger now than for pc games.