A lot of interesting facts posted as well as a lot of interesting opinions. Of course, many times, Opinions turn out not to be facts, so, I'm going to give one of each....
Fact: Nothing says that sensitivity alone has Anything to do with the sheer sound quality of a speaker. I've been building for near 40 years now. This is a fact. Well chosen high sensitivity parts can produce a high sensitivity speaker system. Poor parts OR poor design will produce a lower quality regardless of Sensitivity.
Opinion: way back when, We produced a particular speaker that was 97db sensitivity @ 8 ohms. This particular speaker (15 inch 3 way) sounded great with Tubes and solid state, but man, when you put a really good big mama solid state amp on them with a great power supply, these things reacted with dynamics like non other.
So, my opinion, in general is: High powered solid state amps can be a benefit to High Sensitivity speakers.
Clear as Mud? Tim