I do not find mine bright.
The Klipsch Center Speaker is VERY efficient. Unless you tell your AVR to cut it’s volume relative to the front speakers, it will be dominant, call too much attention to itself.
I would say people are translating ’Prominent’ to ’Bright’.
And, the front speakers may not be toed in enough, thus the highs (narrowest dispersion) of the front speakers may be diminished.
I bought these DBX-Soundfield 100’s new WAY back when from 6th Ave Electronics original store
They are specifically designed to produce wide imaging, (left/center/right of a sofa for instance) and contain 3 tweeters to compensate for high’s narrow dispersion.
Left speaker is angled more to right position, but left person is closest to the left speaker. Thus direct dispersion from right mixed with closer proximity of left gives darn good imaging, Opposite side opposite.
Main music System: I use this alternate toe-in when I have a friend over, both of us off-center. Left aimed at right person, right aimed at left person.
Very decent imaging is produced for both positions. Many of my friends systems, if off center, lousy or no imaging.