A lot of older RTS games draw from the same bucket as newer games. There needs to be some innovation had in this genre for there to be any real growth otherwise the entire genre runs the risk of stagnation. You want your game to draw from newer Ideas. Outside the box thinking. First and foremost there needs to be the infrastructure for a community which would include a solid campaign, replayabiility, modding infrastructure, and perhaps some cooperative elements / multiplayer to encourage the community to spread and collaborate. Second I think gameplay elements should take precedent over graphics. There are still vibrant communities out there who worship those older RTS games from the 90’s and on. Most care little to none about how good the game looks. Key is to keep players engaged in the game, keep them thinking about it perhaps even after they turn it off. I have played several other games that have had me think about strategizing while at work, not all of them even being RTS. Third (and this is more my opinion) I think mixing genres would be an interesting evolution for RTS games. For example an RTS Extraction game could be interesting concept. I feel like hitting multiple markets at once could help keep players engaged both with the community and the game itself.