Wide dispersion + high efficiency + detail + coherence in a speaker?

When it comes to dispersion I think it's a question of whether the off axis response is just lower in volume or whether the off axis frequency response is bad.  When I think of bad dispersion I think of a speaker that has good on axis response but the off axis response is poor.  In cases like this you want to hear as little of the off-axis reflected sound as possible since it's messed up.  If the off-axis response is low in level but the frequency response is still good then I don't consider it bad dispersion. 

No one  absolute champ perhaps  but lots of good options that strike good compromises case by case.   I guess thats why so many choices are out there .  I say go for them all. No rule that says you can only have one system. 

For coherence consider ESLs. Like Quads. Not hybrids like ML.