if mazda wants to create a new RX-7 halo car that competes with the porsche, the new NSX, GT-R, etc -- it's going to have to magically come up with far more than 300hp that the renesis engine is supposedly capable of. or it will have to create a car that weighs about as little as a miata with that 300hp.
1st and 2nd gen rx-7's were affordable sports cars. the early 90's rx-7 was stupid expensive. it's no coincidence that toyota supra and rx-7 are no longer around.
a $40k+ mazda sports car is a hard sell -- less than 1000 cars a year. the only reason mazda would do that is if it really wants a halo car for image. nissan's GT-R is a beast of a car and sales for that are not exactly stellar - about 1500 or so a year - but it brings people into the dealership.
my prediction is mazda creates a sports car that slots above the miata and mazdaspeed 3 in their lineup. and competes with brz/fr-s/370z/genesis coupe.