Well the x/y charge rule has effectively been replaced with a more 'standard' 45 degree flank, front and rear arcs. I've been neglecting the rules myself, so I can't (without going to read said rules) say whether this has been officially changed or not, but it certainly was a trial rule that was effectively adopted by all events at least for a very long time...
Personally I still like the x/y rule as it was something else that sets Warmaster apart from other wargames if nothing else...