DrPhillipa
Why the Bus can not default to sensible neutral values of thrust and pitch (and trim maybe) before dumping it on the pilots I do not know
So many posters know diddly-squat about A320 FCS.... if you don't know why post?
It does not "dump" on the pilots... In alternate law thrust is locked at current value until PF takes over manually, pitch law remains (with auto-trim) the same (1g stick free so no pitch change if you leave it alone), except you lose protections in the event of high speed, high alpha, and big pitch excursions, roll law degrades to direct control of ailerons and spoilers.
If it goes to direct law then you have direct control of elevators as well, and must use manual pitch trim.
In all laws the a/c remains completely controllable by flying attitude.