Sums it up. Players naturally gravitate to the classes they know will give you the smoothest run through the encounter. We're not all perfect, we make mistakes in runs, so people of course bias to the most forgiving classes.
Sch took a hit in 4.0 - they got it wrong. This was recognized with some subsequent adjustments - but the work on Scholar shouldn't be regarded as finished.
Irrespective of actual number output, whether this be heals or damage - it's too 'clunky' for want of a better word. It doesn't give you smooth game play, especially compared to the other two healing classes.
So although there maybe number adjustments in 4.1 - cool down/mana cost reductions etc - I believe it needs a bit more than that to bring back the smooth flowing game play the class had before 4.0