This is full of interesting points.
Benny Morris must be a tormented individual. He obviously has a morbid fascination with meticulously detailing the history of expulsion of Palestinians, sometimes trying to palliate it with excuses, but more often describing it with all its loathsomeness. That he should conclude that the expulsions were necessary is no surprise. The right can hardly welcome him since he did more than any other individual Israeli to eliminate the myth about “Arab orders” leading to the population clearing out; he shows that in nearly all cases the Palestinians left because they were either terrified or were driven out at gunpoint, leaving Israel’s subsequent refusal to let them come back as clearly unethical. What else is left except for some kind of exceptionalism based on ethnic identity after that? But, as he perceives, that will not wash in today’s world, so naturally he is an ultra-pessimist, something like Daniel Pipes.
Morris’s assertion that driving out all the Palestinians in 1948 would have been better is only a speculation. At the time, Israel decided not to precisely because they were afraid of outside intervention. Even had they gotten away with it initially, the number of people oppressed would have been much, much larger, which would have had more foul consequences in the long run.
As for the idea of the Palestinians being satisfied with Transjordan for a state, that has long been an Israeli claim and dream, but it isn’t so, first of all because people don’t like being robbed of their own homes and second because Transjordan=present-day Jordan is too arid. The areas in Jordan which allow rain-fed agriculture are much smaller than those currently under Israeli control, nor are they so productive, because the rainfall is less. Today the Kingdom of Jordan has about 11 million people and all of its easily inhabitable areas are quite crowded. It has one huge problem: a chronic water shortage that will never be easy to solve.
As for the comparison with Turkey, it is not really accurate either. It is true that various terrible ethnic cleansings took place in Turkey, the Balkans, and the Caucasus, but all of these were perpetrated between indigenous groups that were fighting over land. These groups had dwelt mixed together under the Ottoman dispensation, when modern nationalism did not yet matter, but with the arrival of full-blown European nationalism shortly after 1800 and its great expansion as a result of the peace of 1878 that created independent Romania, Serbia, and Montenegro as well as autonomous Bulgaria, all the different identity groups began eyeing their situation with a view to grabbing as much territory as possible, which meant ousting their neighbors. So huge expulsions happened, culminating in Turkey’s continuous wars 1911-1923 which led to more ethnically homogenous states in the entire region. Turkey suffered greatly too, as the demographer Justin McCarthy has shown in his book Death and Exile, with as much as quarter of the current Turkish gene pool consisting of refugees that were taken in from other areas. This does rather contrast with the Zionist project of settler colonization, which has been throughout more one-sided.