The inference seems to be that if Mossies were used there would be no, or fewer, casualties. Would that be due to speed or structure? Certainly not due to defensive firepower. How many crippled acft would return to Britain with one or two engines shot out? How would an injured pilot be assisted at the controls to bring the plane home. Since it seems twice the number of acft would be required to do/deliver the job, would aircrew losses still be less?
See my post on bombing accuracy and per-mission survival rates.
The truth is however we don't know how many Mosquitos would have been destroyed in a 'What-If' scenario, I certainly agree that the Germans would have adapted to the new strategy. Do you think they could have shot down as many Mosquitoes as they did Lancasters?