I read the same thing about the Mossie/Lancaster debate in a quarterly aviation magazine. The thing to consider here is that a Mossie could carry almost as heavy of of a load as a B17 and the Lancaster carried even more
I think the text in the magazine was "the Mosquito was a precision weapon, like a sword, while the Lancaster was a crude area effect weapon like a bludgeon"
It's an interesting debate but i tend to agree that if enough Mossies could be built they would be a far better alternative to the thousands of 4 engined RAF heavies. They had as much of a carrying capacity as the american daylight bombers, better accuracy in their drops (especially if you add some Oboe equipped Mossie pathfinders in the mix, while 4 engined heavies dropped their bomb loads over empty countryside for much of the early stage of the night bombing campaign due to navigation difficulties), lower chance of interception by the enemy and probably better crew survivability rates in the event of a crash, which the Lancaster was notorious for.