Based on those frequency response curves alone, I'd say these speakers have a pronounced bright sound.
The red trace (on axis) and the blue trace (30° horizontally off-axis) show a broad dip in response from 200 Hz to about 2,000 Hz (compared to the bass below 200 Hz), and then a generally rising response from 2,000 to about 10,000 Hz. This is likely to be heard as a rather bright sounding speaker.
I'm not sure where the crossover frequency is, but guessing from the traces, it might be somewhere around 1,500 Hz. That suggests the tweeter is voiced too hot.
There are 2 bumps in response at about 400 Hz and 2,000 Hz that I think will easily be audible. They might also contribute to the overall bright or even harsh sound. If you look at the impedance vs. frequency response (black trace below), they correspond to irregular bumps at the same frequencies. One of the posts in your link (from Robert Cook) said:
I'm thinking that these resonances may be contributing causes to the honkiness and listening fatigue that many people have experienced with modern Klipsch home speakers. That resonance at 400 Hz happens to correspond precisely to the outer circumference of the horn, which must not be adequately braced and damped, allowing the horn to literally ring like a bell. And the 1200 Hz crossover frequency for the high-frequency driver means that its colorations, whether detectable in these measurements or not, will be present throughout the midrange.
I think he may be right about that.
There are also some irregular peaks at around 18,000 and 20,000 Hz, but I think they will be much less audible than those midrange bumps.
The impedance vs. frequency curve also shows undesirable features.