Good question Si,
The differances between hard and soft snow are that the support point relative to the center of effort through the foot varies. On hard snow we lever the ski up onto its inside edge which is offset from center of foot (this is why most alignment protocols position knee alignment somewhere between lateral center of boot sole and it's inside edge). In soft snow we roll skis around the center axis of the ski base, with some ski displacment, until the base compresses the snow enough for desired support. The reduced leverage soft snow requires may mitigate the perception of any alignment issues, but I'd rather be aligned in either case.
The bowlegged (over edged without alignment) skier probably benifits from the reduced leverage required to edge in soft snow, in that the center of effort is under center axis of foot (closer to where thier knee is aligned) vs. way over at inside edge of ski.
Note: Even as a well aligned (from slightly bowlegged) skier I was very aware of the leverage varations when on a 78mm waist ski in conditions varying from packed to soft snow. In those same conditions on my 64mm waist ski the variation was negligble. On the fat boys my edges are 7mm further inside my knees on hard snow, but knee position relative to center axis of ski base was unchanged so in soft snow they felt fine. After a day that included some very fast milage on hard pack I felt additional soreness in knees and new soreness in my hip flexors from the magnified leverage of the wider waist. Even tho my boots are ground, I'm considering canting my wide skis to move my knee in a little to a stronger relationship to the edge location.
The knockneed (underedged without alignment) skier will have problems on both conditions, difficult get to edge on hard snow, and difficult to compress snow for lateral support in soft (but soft is probably more fun).
The perception of alignment not mattering in soft snow may be that many skiers would usually rather ski powder than hardpack, aligned or not.[ December 19, 2002, 11:27 AM: Message edited by: Arcmeister ]