Hey guys, what happened to the OP?
I'm wondering here why no one has brought up...power? Speaker size? Excursion? All these aspects would play a role in the "impact" arena...right? When thinking of the impact of real instruments, I relate to percussion...I'm a drummer

Size: Look at the snare, it's only 14 inches in diameter in most cases. If someone gives it a whack and you're near, you'll feel it. Move away, its gone. Kick that bass...22" and you'll feel the impact up to a couple meters away and it fades, but still audible. Power: transients focus a LOT of energy in a narrow band and if your amp is not up to it, you can't push the speaker enough to excite enough air to feel the "impact". Excursion: Ever seen what happens to a drum head? Those things move a lot of air...so must the speakers to feel the "impact". Bass vs tom-tom here.
All this to say if the people on the other sites the OP referenced are saying that an OB with one tweet, one 10 and maybe a 15 using a 100 watt amp with passive crossovers lack impact...well yup, it likely will. I found this out with my first OB and I was looking for the same thing...impact of the transients; to feel and hear the music like I do when playing. I ended up with multiple drivers, four crown amps and dsp. Now I have "impact".
Just my thoughts, nothing scientific.

Brad