In your opinion, what is the best real-time strategy game?

You're just whining, Vissy.

Do you even know what that word means? Or are you just randomly throwing it around, hoping to hit the mark? What exactly are you whining about? Because two people who are feeling nostalgic about Dune 2 said something different from your opinion? Lol.
Dune 2 was an amazing game for its time.
And your arguments about the "awful interface" and "stupid controls" are not worth a damn.
It's just nostalgia. I played it so much that the game is dear to me, and I'll keep saying that everything in it is good, even though it's not all good.
The interface is awful: to build a building, buy a unit, or even just repair something, you have to go into its individual menu and click on the corresponding icon. "Attack," "move," "stop" – it's so convenient, isn't it? And moving a group of tanks from one end of the map to the other is just a wonderful and unforgettable experience. Seriously. When it was relevant, yes, it was cool. We'd play Dune 2 in the evenings with tea and cookies. But would you play it now? I installed it and couldn't play. Unlike Dune 2000, which I have installed on my laptop.
The comparison with Diablo is a bad one, a very bad one.