very few people know what it take to truely build low distortion high-output drivers.maybe 5 people here can answer the OPs question. everyone else is pretty much talking out there ***.
low distortion has NO sound. its transparant. no warm or smooth tight or punchy. it simply plays the signal as intended.
its alot easier to get a driver with low mass low throw and low inductance. much harder to get a high excursion high output high inductance driver to sound good.
typically your "sq" drivers are short throw high efficency drivers. 10-12-15 size doesnt matter becasue it has great efficency. Id almost argue larger drivers are capible of sounding better because of the increased efficiency and lower excursion for a given output.