Well, there are rts for mobile out there, so someone is doing it. You need object pooling and a few things like that, and you would probably need to limit the number of enemies somewhat. If this is your first game or something, then an rts might not be the best choice. Some AI behavior makes games a lot more interesting, but it doesn't need to be extreme or anything. Maybe you could even do match 3, but you need to make it look and even play a bit different to set yourself apart. Gameplay is something you might need to copy a bit at first, but then let it evolve in your design process. Like, what if I did this, how would that work, so you need to take your time with it, especially if you intend to sell it. Keep working on the graphics, gameplay, etc. Part of it is choosing something you yourself enjoy. If you don't like puzzles, you probably won't write a good one. The good part about mobile is it will force you to do a small project and that's what most indies should be doing because the completion rate is terrible for all of us.