I'd rather play those two games using OpenRA. Releasing Tiberium Sun (> 20 years old) RedAlert 2 (also 20 years old) would be a great move that actually made a difference.
I've found Generals fun too. Specially multiplayer.
I would absolutely love to see the Tiberian Sun engine's source code. The graphics setup is totally unique-sprites and voxels coexisting in a 2.5d world with lighting. Lighting! Used to great effect in the dark and grimy graphics.