Janeway's line at the end about seeing them again bugged the hell out of me though because it's obvious that Voyager will never encounter them again. They'll forget everything that happened in this episode by next week.
That annoyed me, too. Why bother throwing in that line if the writer's have no intention of revisiting the Vaadwaur?
Reminds me of the throwaway at the end of TNG's Conspiracy
The Vaadwaur were supposed to return at some point. I think the writers were a bit unhappy with the execution of this race and just decided to not bringthem back.
The Conspiracy aliens from TNG were part of an abandoned concept that eventually became the Borg. Originally the Borg were going to be a race of humanoid insects. I think make-up issues made that too expensive an idea so it was changed into what we now know as the Borg.