The GWX guys (and many others) have done an amazing job with Silent Hunter 3, but there comes a point where without enhancements offered from the publisher, the game reaches the 'as good as it gets' stage. I think Silent Hunter 3 is pretty much at that point.
The U Boat development of Silent Hunter 4 on the other hand is in its infancy. Lurker's Beta mod is a big step in the right direction, and he and the GWX guys deserve a lot of credit for the work they are doing with Silent Hunter 4.
To have both a Pacific fleet boat campaign and a U Boat Atlantic campaign within the same game is awesome to me. I look forward to many future mods.