So what are the points in which it could not turn out well?
In Junes Jolla communique regarding sony i hope to have confirmed the following.
Most important sure is that Jolla treats the port like any other of the original devices. That is suggested by them calling it a community device which implies same procedure as with Jolla C.

Hardware support should still be offered by sony for obvious reasons.

Official release of the image at some time to help yourself if the device breaks while out of warranty time and simply flash a new (used) one and solve possibly limited amount of preflashed Xperias to be offered by jolla.

What (apart from the refund option) would you expect from this port / community device to make you feel good.