In the most recent update, after getting the diamond ore spawning upgrade gold ore no longer spawns. I have not reset my save between updates (just in case that's related to the problem)
My first time playing (three updates ago) I felt the early game was a bit too slow but the new systems introduced have improved that experience and I've found that the rest of the game is well paced enough as is, the only thing I'd like to see in the future is an option to choose what ore the auto miner targets first or which order it will choose to mine in.
Either way, Continue the good work!