An 'explore resources' command would seem like cheating, at least until you researched a tech that could run long-range scans for them.
If by "explore space," you mean "run a logical map-revealing pattern in coordination with other units running the same task," then I've been waiting for that since GalCiv I and would jump for joy to see it finally happen.
I never thought about an explore command that focused on star systems, and that also sounds like a mighty fine idea.
