Command & Conquer Rivals launched this week, bringing the storied RTS series to mobile. Against all expectations, it's actually pretty darned good.

No, it's not the full C&C experience as series vets might remember. But it does provide a mobile-friendly tactical experience that deftly works in elements of the franchise.

All of which got us to thinking about all of the other classic RTS series that we'd like to see coming to mobile in some for or other. Whether that's through a direct port we're not so sure, as many of these games are pretty complex and large-scale.

But if someone could nail the core essence of the following four RTS games on mobile or tablet, we'd be very happy bunnies.