Oil usage is not as high as people think, they use about a litre a month and is a necessity, though most people that tune the older rotaries run them premix with a 2 stroke oil.
Most failures are down to owner ignorance as it is an unconventional design.
An RX without a rotary is just an mx5, it would lack the high revving character of a rotary powered model. Its what mazda do and they can do it well, the old n/a FC would do 120k + before needing work. For me the wankel would make it, much in the same way as the boxer engine ruins the gt86 for me. A high revving motor with a beautiful exhaust note coupled with the good chassis mazda are capable of producing would make up for the ''lack'' of power / torque ( even though torque is a grey area, its like comparing 2 & 4 stroke motorbikes )
More to the point it would likely spur Nissan to build the s16 and that'd be the one to watch out for as it would likely be turbo'd out of the box.