1). Strategic zoom, something which so far I've only seen recreated in 4x space games 2). Advanced economy that allowed for incremental spending, i.e. build yourself a monkeylord, and that thing will cause your mass to go down by 4 for 2 minutes, not an instant 400 mass 3). Intuitive queueing. It's super easy to setup crazy tactics with shift-clicking, and when you are zoomed out and hit shift you see all queues you have setup 4). You can fucking schedule your shit! Have your bombers fly in a delayed manner to attack the base at the same time as your ground units.
That game was epic and awesome, and if you disagree with me I can say with certainty that you never spent the time to learn it.