The idea of a Nissan Miata fighter has been running hot and cold for some time. Actually, more like warm and cold, and the situation is trending toward the warm once again. This shift in temperature may have to do with the Esflow Concept that Nissan featured at the ’11 Geneva Motor Show. While the electric Esflow is a long way from a Miata fighter, the buzz is leaning toward a roadster built on the Sentra chassis, but a Leaf-based drop-top is also a possibility. The Miata is a seductively balanced driver’s car, and we’re surprised automakers haven’t already tried to do its formula for success one better.