Presumably, "running them higher" means a higher hpf setting, so you could be getting higher, more localizable frequencies from the subs. In addition, the transient peaks of a kick drum for example are not limited to typical subwoofer frequencies but extend much higher, exacerbating localization with subs with a higher than typical hpf.
It sounds like you have the problem licked by placing one in front and one behind the listening position, which is all that matters. It goes to show how each room is it's own idiosyncratic acoustic nut to crack, particularly for bass.
FWIW, you're not the first I've heard mention something along these lines (a strong preference for forward located subs for the sake of realism-the music should come from the front, after all). Since true sub frequencies are nigh impossible to localize, I think in both yours and the other fellow's cases it concerns higher freq content (above 80 hz, up to whatever you have the subs low passed at).
Keep on rockin'.