In an interview with Automotive News, Mazda CEO Masamichi Kogai responded with a simple "No" when asked if Mazda has plans for a larger sports car entry. Kogai was asked if Mazda has any plans for a production rotary. He said that the 1.5- and 2.0-liter engines in the Miata are more exhilarating. That's a debatable and subjective argument that thousands of rotary owners both past and present would likely disagree with.
It's more likely that despite ongoing development of the Wankel, Mazda is still struggling to meet emissions standards. Despite the advantages of a rotary (high power-to-weight ratio, compact size, rev-happy nature), it's not very fuel efficient and struggles with emissions testing. Also, despite the prestige and attention a halo sports coupe could potentially bring, Mazda is a small, independent automaker that needs to focus on mass appeal. Creating an all-new design with a unique engine isn't cheap.
Badging a non-rotary car as an RX would be sacrilege, so don't expect an RX anything anytime in the near future. Current RX owners should take a moment to lament. Their car probably needs another quart of oil anyway.