Assuming LR4 at 2100Hz woofer is attenuated by app 35dB at 5400Hz. Are you saying that is not enough?
Note that the crossover slope and the electrical filter are necessarily different. The crossover slope is the combination of the drivers' respective inherent responses and the electrical filter. So the electrical attenuation is less than the acoustic slope, and a large breakup can still have a measured and audible effect.
We do not know the individual driver slopes, we do not know how big is the cone breakup peak, so we do not how much lower in level compared to the summed response. But we see that peak about 5 kHz, so ...
I noticed similar behavior in a competitor, Monitor Audio Silver 1. This speaker has a similarly sized woofer and nominally 4th order crossover. It also had buywire/buyamp terminals, so I could measure the woofer and tweeter separately. The figure won't show if I paste it here , but see "Acoustic Crossover..." here:
https://hometheaterhifi.com/reviews...-audio-silver-1-bookshelf-loudspeaker-review/
For this money you can buy Neumann KH120.
While in terms of sound quality per dollar I think it's agreed that studio monitors from companies such as Neumann usually top hifi speakers, sound quality per dollar is not the only metric by which one should judge speakers.
These Revels are finished very nicely. When this series first came out I attended a demo set up by Kevin Voecks. He was showing Salon2 and the then new F36. Both were piano black. The finish quality was surprisingly close. Not identical, but I'm also not sure the differences would be apparent if they were in adjacent rooms instead of side by side.
By contrast, while Neumann uses quality materials, their industrial design is more utilitarian than luxury. If that appeals to someone and works with their decor, then they are excellent options. But fancier cabinetry has a place too, and may be the difference.
Revel should also have greater output capability, though Neumann may perceptually match that to some degree with creative use of limiters in their tightly integrated package.