To be honest, I’d like to see them come back. But for new patrol zones, I’d want this: https://imgur.com/a/kQC4MzY
The Dreadnaught has a lot of potential to it. It could basically be a Hive version of the Leviathan. The Cosmodrome, because it's relatively small compared to other places, would likely need a drastic face-lift again much like what it received in Rise of Iron to make returning to it valuable. There also isn't really a lot of strong lore potential tied to the Cosmodrome. They had to invent a plot device in order to make returning there reasonable, and we all but neutralized that plot-point. I'd rather see a new environment brought to light (An extreme cold arctic-esque environment) or a return to regions that either haven't already had a revisit or have good story potential.