As you progress up in levels, you should be able to carry more than one drone. For instance, an Engineer class should be able to carry a maximum of 4 or 5 drones, and be able to set them to various tasks/preprogrammed routes.
Also, drones really need to be upgradeable for things like faster speed/larger storage capacity.
Finally, drones really should be able to be assigned “routes” with waypoints, for example, being able to assign a drone to harvest multiple squares, until your inventory is full, or, if you are on a square with a Vault on it, as long as you deposit before your inventory is full, the drone will continue to harvest squares along a preset route, until they have been exhausted.
As a secondary function, drones should be able to be configured as sentries/attack support. In combat, you could have a couple in the air watching your back, especially if you’re outnumbered.
This will make gathering resources/defense much, MUCH faster…