At the pace Voyager was zooming through the DQ (and BQ?), Voyager shouldn't really have too many recurring enemies.
I mean, I thought we were past the Borg in "The Gift," but nope (although I suppose transwarp conduits all the way to Earth allows them to roam wherever).
The Malon and fat Heirarchy aliens sure seemed to have a lot of space.
At least Species 8472 could open fluidic-space rifts wherever.
Voyager tried to play it both ways: have recurring aliens and also quickly getting home in the last few seasons. Those two don't mesh well logically, but I guess the studio didn't want to constantly be making elaborate new costumes. Although, time travel did allow that to work ("Before and After" with the Krenim, "Shattered" with the Kazon).
Out of all the recurring enemies, the Malon and Heirarchy fatties were my least favorite. I did like the other Caretaker's Ocampa as enemies, but I didn't like Kes as an enemy (although I did like seeing her again).