I was thinking about doing something with in-game shots too, but at that time I didn't have any skinned units for the mod ready. Your picture looks good, but I don't think we should have that much fire, and rather stick to a realistic-looking color scale, for the sky. A real sky at sunset looks red enough IMO.

For loading screens in general I think a mix of calm natural views and battle pictures would be good for loading screens. Also, for the battle pictures I think it would be cool if we used a more complex terrain and arrange the exact battle scene we want in a custom battle or in multiplayer with each other to get the pictures we want.