For me Dessers misses easy chances, doesn't hold play up, falls over far too easily, is constantly trying to make friends with officials and opposition players and has the first touch of a blind baby elephant.
He has short decent spells (like his mini recent scoring spree) but then reverts to type and we get a handful of matches where he plays like he did against the scum. His whole career has been like that, so it's unlikely it'll change.
Comparing him to McCoist is pointless. McCoist's job was to score goals. Forwards have to do a lot more these days.