I think you're pretty much got it correct- except I wouldn't say the bittering hops give NO flavor from them. I think you can still taste chinook, for example, although it is slightly different than say, nugget or warrior.
I would also say that the bittering hops matter less in a beer with lots of other stuff going on- (IPA) but more in a beer with less other strong flavors.
I've been bittering with high AAUs myself, and saving the cascade, simcoe, and amarillo for flavoring and finishing. I would say the difference between using cascade and warrior for bittering in an APA or IPA would not be noticable, or at least not undesirable if noticed.
Edit- yeah, what he said.