One thing that I really miss is an option for a transport to wait on a planet until it can fill its cargo with something you order it to Load, instead of just failing to pick up something.
This would make it easier to make cycling orders for pickup of installation as you don't need to calculate how much you produce and inserting wait orders so the planet never have anything to pick up.
Sure... you can end up with a transport sitting there indefinitely as it tries to pick up something that will never be built, but that would be a trade-off I'm willing to take as it would be an optional order type.
There would need to be a check if multiple fleets are waiting for the same thing as only one such fleet should load something at the same time.