Well please understand that this will not be an exercise in objectivity...
The Desmosedici (which I know you had) was unique within the Ducati range..was basically a "dumbed down" version of a MotoGp bike and therefore commanded a price which reflected this..ie $circa $72000
Now the SL is a suped up version of the 1199... The engine ..whilst somewhat modified..is a 1199 motor... the output is "in excess of 200hp".. so not really a paradigm shift from my $19000 base..
The weight savings are not great ..20lbs ish...If I added Ohlins/Akra to my base and had it tuned using a power commander I bet it would be very close to the equal of this bike and save me in excess of $35000.. Its shouldn't be possible for me to modify my bike and come even close this cost effectively...but I can in all the important ways anyway...
I don't want to get exhaustively into the differences..
I think all in all its simply not worth a $45000 premium over my bike ..All this is my opinion...one that carries no more but also no less than anyone elses..