RWA
Agree with your post as well as Man Flex; Have discussed the THS with a few colleagues & I don't see what benefit there is in allowing the THS to remain in a position (that would most likely render the aircraft unflyable) without manual re-trim following reversion to alternate law.
Indeed, (and without knowing the typical range of THS movement during the cruise phase of flight), I can't see why the autotrimming isn't limited to a degree or two beyond the "normal" cruise range, with a warning that it is reaching the limits of its "normal" travel. I doubt that more extreme manoeuvres such as TCAS RA or Terrain avoidance would be hindered significantly by such a limit.