You have to decide
: Did the NS10M sounded so dreadful because of their goal of flat power response? Because of the big woofer size for a two-way design? Or both?
A pulsating dome may be omnidirectional, but a rigid one cannot be. At wavelengths approaching and above the diameter they beam and, depending on the shape of the dome and the behavior of its surround, there may be interference effects. Again, don't trust me, look at the data.
But I always trust in the man who brings reliable data!
"In God we Trust, all others must bring data” W. Edwards Deming
However, you have to agree that, as far as transducer behaviour is concerned, a dome midrange of sensible size and shape will always better resemble a tweeter dome than a cone of the same radiation area as the former is able to, all other things being equal.
The problem with domes is that once they start to exhibit breakup modes there's no way to control it, as opposed to cones. That's the reason why beryllium is used here at such great effect, because being as rigid as it is, it can assure perfect pistonic behaviour for an extended frequency range.
I guess that's the reason why Focal started to use the so-called inverted dome tweeter and then they just applied their long standing technology to beryllium. It's my belief that with beryllium they wouldn't have need inverted domes in the first place...
One must admit that, the single most important progress in the loudspeakers design in the past 15 years has been the materials technology used in transducer manufacturing, greatly influenced by the increasing sophistication in software simulation.