I have no localization issues whatsoever.
I have 2 SVS SB13's up front and two PSA 1500's in the back. These are connected to the receiver through a MINIDSP 2X4HD.
The room is about 22' x 11.5' with two openings and also an open stairway to the upper level. It is a living room and in no way designed for sound quality.
The speakers and subs blend better with a high crossover. I have tried every crossover from 40 to 250Hz. Anywhere from 130 to 200 works pretty good. 150 sounds best but I get the best looking measurement at 200.
I have tried the LX's with no subs. In my room they are just a bass heavy mess. The bass between 40 and 80 Hz has a 20+ dB hump. Sounds something like that cheap subwoofer in a car trunk going down the road.
This probably explains why I thought that the detailed upper frequencies where missing with the LX's. They where drowned out by the elevated bass levels.
Blended with the subs they sound great and I do hear an improvement in the midrange.