The midi range, not the tweeter, is the most important driver in a speaker.

This is wrong. If mids were the most important why dont you just buy yourself a pair of ATC midrange domes and stick them on some stands and call it a day? 
That would never sound high end. 

There is no such thing as the most important driver. Every driver is equally important DO NOT BE FOOLED

@teo_audio 

Yamaha ns-10, a horribly distorting speaker

They are too revealing not distorting. They are used by the best recording studios. They could choose any speaker they like. 

My point is still the same: We focus way too much on the type of tweeters we use, and not on the driver that outputs most of the mids.

Thats because not everybody shares your opinion.