If by mastering the basic games you mean you have developed a couple of the games mentioned above then I don't see why not. A top down rpg or some creative twist on 2D rpgs wouldn't be too far off.
If you don't have much experience now and are wanting to learn C++, while building a game, find yourself a good book or reference for C++ and program a text based rpg or text based adventure game. That may not sound too interesting but I think you will learn that they are a lot of fun to create. You will be amazed at how much you learn about a language from coding that style of game as well.