There's a lot of conflicting 'legal opinions' floating around at the moment, so it'll be very interesting to see how this plays out in a real courtroom with appropriately qualified legal practitioners. I get the feeling that the Doctor doesn't want an out of court settlement.
That's a good summing up.
It's reasonable and predictable that there is disagreement among the legal community about the relative weights of Conditions of Carriage, on one hand, and the absolute right (if it exists) of a company to kick an individual off its property (made more complicated by the fact that the crew of an aircraft have wide-ranging powers).
That disagreement is only going to be resolved in a courtroom, and it's probably in United's interest - though not necessarily that of the travelling public - that it never get that far.
I expect the following outcomes:
a) Dr Dao will reluctantly forego his day in court, on the advice of his lawyers, but will become a very rich man
b) the legal situation will remain as muddy as before
c) the industry will pay lip service to the lessons learned, but until those at the top wake up to the fact that they are running a customer-focused business, nothing will really change