Space rts tiles

[Cobalt Blue]

You'll have readability issues with straight on top-down, imo it is the yuckiest view to work on.
Maybe tilting the perspective by the x axis by a few?

Dune on the Sega Genesis had no problems to make nicely readable buildings in a top down perspective.

for a Tiled RTS, is the best way to work. problem is that the colors used in the floor and in the buildings in this case is so similar they end merging each other. its just a matter of contrast.