Nothing intrinsically wrong with the Scala, just like most anything else... Something definitely wrong with the ears of many of it's players, though!
I mean, after all, what's the point of all that theoretical superiority over 'closed' arrangers, if you use sounds that are inferior? I guess when I REALLY need sounds a LOT better than my G70 in a live situation, I might have to look into a Mediastation, or Muse Receptor. Trouble is, right now, the ones already in just the basic ROM (don't even have an SRX card, yet) tend to blow away anything I've heard out of a Wersi, so far. And are keeping some of the pickiest ears very happy in the studio. And mine, too (even though I have quite a few good VSTi's)...
All without any of the complexity of running a VSTi rig live, or of course the weight penalty of a Scala
From what I have heard of user demos on the T3, G70, PA2 etc., despite some terrible ones, on the whole I think that most players can achieve at least a decent sound (better than most achieve on the Wersi's). And some of the better ones beggar the question... If a $3500 arranger can be made to sound THIS good, who on earth would spend $30k+ to sound only slightly (if at all) better?
I take the theory of diminishing returns pretty seriously...