I started making "retro turn-based RPG" thinking there is a shortage of these. But when I received comments (after posting on RPG sites/forums) I was very disappointed. No one really needs a new RPG, they don't say "yes! finally someone is making a retro RPG, we were waiting for it for ages" instead they ask "how it's different from thousands of RPGs made recently"? In retrospection, I regret starting that project, I would do much better focusing on another genre.
You probably could do it, but only if it's a very high quality (preferably AAA). But you won't get any novelity points for making retro RPGs, it seems the market is saturated (don't ask how, I don't see all these new RPGs being made, hust judging from the response of RPG fans).