usually the 3 way crossover causes more problems in a build than good, however if you are willing to spend great deal of money you can get something real good.
https://www.soundonsound.com/reviews/three-way-active-monitors

 

Most of the greatest mixing/mastering studios adopted a 3way design and worked on them for decades, that alone proves that a 3 way design is not a bad choice. Yes, it is harder to design and manufacture (on the company side) but in the studio, the end product has no issues whatsoever as long as the room is big enough and acoustically treated. Yes, 3ways tend (in many cases) to be packed with enough power and an extended bass response to run as mid-fields as well maybe that's why it sounds problematic in many (small/untreaded) rooms. They do demand a better monitoring enviroment to be put in but in the end, the extra mid driver allows that specific frequency area to work more efficient at what it was initially designed for.
There are indeed expensive 2way speakers beautifully crafted and designed, but if that same design would have a bigger "3way" brother, like Amphion One18 against Two18, Eve SC207 against SC307, ATC SCM20ASL 2way vs SCM25A Pro 3way, sonically you'll always pick the bigger model hands down, BUT, as long as you have the ideal room for it. In a small room the smaller 2way will work better.

 

I agree with you fully.

 

APS Trinity :

http://www.aps-company.com/trinity-en/

 

Must be awesome monitors, but not cheap @ 6000euros, 37kg each hyper heavy, no much info around...

 

There are always some hidden marvels out there, that can make big boys(mainstream brands) uncomfortable. Not 3-way and not powered, but i believe this widely unknown French brand is one of those, if heavily advertised(like most big names), would be at top of choices.
http://klinger-favre-english.blogspot.si/