Soundstage and explosive dynamics?

^ There are plenty of large cone drivers can be driven to high levels with low power.

Many of the ubiquitous 3-way, narrow baffle, ~$3k towers can do dynamics fairly well, but I haven't come across any that can produce sound with the sheer scale of something like Klipsch Cornwalls. 

^Many huge speakers require very little power and volume for excellent dynamics. This would be glaringly obvious if you were to compare some volume-matched Altecs and some narrow-baffle tower speakers at around 70 db. What you’d find is that the lower efficiency tower speakers require the louder volume to come alive.

Some consider dynamics as simply chest-punching upper bass. That’s what the narrow baffle, 6" woofer tower speakers tend to do well.

What the large horn speakers can do (with only a few watts) is create a realistic orchestral crescendo, or a kick drum that gets eerily close to the real thing. Yes, they have to move a larger woofer, but the woofers typically have very light paper diaphragms and are designed for low excursion. This allows them to produce very fast bass. Subs OTOH are usually designed with much heavier diaphragms and suspensions. They’re also designed for long excursion. This is why comparing a 15" horn loaded bass driver to a typical subwoofer is useless.

Anyway, the most dynamic speakers are large speakers. As others have mentioned, it’s basic physics. It’s why most "class A" full range speakers are monolith size.

The OP has a $10K budget and shouldn’t have much trouble finding speakers that meet his criteria, horn loaded or otherwise.

Every speaker design has its tradeoffs. If it’s not low-level dynamics, it’s tone, coherency, imaging or something. I currently have 3 pairs of speakers in 3 systems and each have their strengths and weaknesses. In Kosst’s defense, horns tend to have a love it or hate it sound, despite all the things they can do well. While I like some horn speakers, I understand why others don’t. I think everyone here can agree that some speakers can manage surprising feats, despite their size and lack of efficiency. For some, a pair of KEF LS50s would be plenty "dynamic." After all, that’s a subjective term, and for which system context must be considered. For my tastes, a pair of Spendor SP100s or Harbeth M40s would meet all my needs, but someone out there would certainly find them anemic by their standards.