Real question is can they get the direct inject down on the Rotary? If they can do that, than the emissions will be lower and possibly be able to turbo it. That was one of the killers of the RX7 in the US in 96. They switched to the OBD II emission standards.
Second, why would you choose a convertible in a handling car? Added weight and probably losing the 50/50 the RX models have been known for. I know they had them pre-FD.