I don't know the speaker, but dialog intelligibility is a HUGE problem, and a large part of it lies in production. Running the center hot may help. Some of the problem is also in the speaker itself and even more a factor is the acoustic environment. I don 't know your speaker, can't say anything about it specifically. Often you can help dialog with auto cal systems like Audyssey, which has as one of its goals dialog improvement. If you don't have it on your AVR, look for it next time you upgrade. It's not a sub for fixing bad room acoustics, but it does help a lot.
Bad room acoustics, in general, are very "echo-y", to use a bad colloquialism. Hardwood floors are again popular, but don't help dialog. I'm seeing rooms now where all surface in the room are acoustically reflective, with so little absorption in the room that the audio is a swimmy mess. Don't know what you have, but when I get a dialog complaint it's nearly always because of the acoustics. But like I said at first, it's a production issue too, so even with perfect acoustics dialog can be challenging.