Wheels vs Atmo thrusters
We need some sort of gating for atmo thrusters.
As it stands, if you can make a rover, you can also make a flyer with atmo thrusters.
Which takes away any impetus to make rovers at all.
Suggested progression: Manual mining->Rover->more mining->flyer->hydrogen thruster->space->platinum->ion thruster
Which means we need something to unlock the atmo thruster.
For example, if titanium was only found on the poles, and was used to make atmo thrusters, and we always landed at the equator, then we would have the impetus to build a rover to drive to the poles and mine to build a flyer.
As it stands, we only do rovers for a laugh.