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

There are Tannoys that have all that, except maybe only moderate in dispersion (which aids efficiency and ease of integration into rooms)

You won’t sacrifice detail and clarity with OHMS if set up right. You will hear it all. There will be so much going on you will just have to decide what to focus on at any particular time, similar to a good live performance. They also compete in coherency with anything. Hence the name Walsh "coherent line source" driver.   Lots of bass.  There are even step up models with built in integrated powered subs if needed.     Set up right, the whole line sounds similar so if your room is small or you do not need the ultimate bass smaller less expensive models will do. 

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.