I can see your point AoP, but would have to disagree. I understand your point on the predictable attacker/defender stance, but the same thing could be said about BF2 any many of their maps. Claymore here, support guy there. Which is one of the reasons why I stopped playing in the first place. But it's not limited to only those FPS games. Look at any Online FPS - Counter Strike, COD, AA. All those games have predictable game play.
However, there are two main factors that make the game play predictable.
1. Limited amount of variety in - Hand Held weapons, Vehicles, Classes to play or any sort of special abilities.
2. Level Design - Some level designs are just not as complicated as others, which makes it seems like there are so few ways to go and you find yourself repeating the same course of action.
Sewer in ET:QW has both of these. Very little vehicle variety (and very unbalanced at that), plus Sewer is a pretty basic map. I do think if there is a Beta2, that Valley will surely bring a nice refreshed look at the Enemy Territory game play.
P.S. I also think we are all getting sick of all these Beta parts of games since it's only 1-2 levels to play on, so if you really like the game, you'll play it over and over and over. But you will burn yourself out faster because there is no change of scenery.