My sense of the speaker (unheard) is that it's fixable with either a treble tone control cut and/or listening off axis with possibly a foam insert in the port to reduce the 500 hz resonance. You'd likely need a sub if you did the port insert. My personal experience (which is admittedly with standmounts) has been that I've never had speakers that didn't benefit from a subwoofer.I could be wrong, but I have assumed the "Target Goal" (As per Harman) for "in room" to fall at the rate of about 1db/octave.
I have redrawn the line to show approx. that amount of slant from 100hz upwards. That may account for Amir describing it as a good bit better than the curves show. Still strong in the treble, but to a good bit lesser degree.