Rigma,
Have you thought about trying a higher power and higher slew-rate SS amp, just for grins? (No kidding here.) Also, getting driver phase delay corrected may also help, assuming you haven't already tried this (but you probably have done this...).
I recall that impulse and "sizzling" cymbal response is something that Bob Carver tried to duplicate using some really high-end monitors and an unbelievable amount of power in the mid-80s. He was using a pair of scissors to cut a sheet of paper, if memory serves. I don't think he was successful in duplicating the real sound even from a system that would today cost $100K+.
I would also wonder if using some hf acoustic treatment between and above the speakers to absorb rather than diffuse hf energy, but leaving the back of the room (behind your head) "live", i.e., a dead-end live-end mixing room concept. A few unused comforters or blankets arranged on the wall between might be useful for a test.
Regards,
Chris A.