"It would be awesome if your planets auto-mine gold": I'm thinking about making the life of gold diggers easier :D. Any other suggestions like semi automatic?
This will make the two upgrade paths: "mining quantity" and "unit quantity" unneeded... I believe that these just cloud the game-play. To be honest, at first, I was considering only upgrading the quantities in stead of the speed because I got tired of the constant clicking, were it not that the mining speed and unit build speed are the important upgrades... I do not see how the quantities will help you win the game.
I haven't tried the game sufficiently to have an opinion on the other upgrade paths, such as attack/defense/range/speed.
Hope this helps...
Cheers
The more planets I get, the more tedious 'work' I have. I found it unbearable above 20 systems (about half were lvl 3/4 in both speed&quantity).