bear, in re words and terms, and a little too much "all or nothing" in your reply:
A/P is "required" by SOP via Airbus, not in some mechanical requirement.
Leaving the controls alone is not unwise in turbulence, where "maintaining" trumps "maneuvering" yes?
No. You make an assumption there, that not having A/P available means that controls are left alone. I respectfully disagree, having flown in turbulence more than once, with and without an autopilot function (though not on an Airbus, of course).
There is one other interface in the mix that gets little attention, that being auto v. mechanical? The Sidestick would seem to be an attempt at "feel" retention.
Not as described in a myriad of posts by pilots who fly Airbus airliners, no. You and I may have gleaned different messages from same posts. Perhaps I am the one misreading.
As such, perhaps jcjeant's touchscreen would be a more honest approach?
No idea. Haven't tried to fly a plane by touch screen.
The THS is powered by a jackscrew via hydraulic pressure, not the speediest method of response.
It seems to work pretty well, doesn't it? I don't know if speed of response is the critical metric, given that rate damping and control damping are features common to various FBW aircraft, as well as some AFCS and EFCS suites in non-FBW aircraft.
I also recall that the elevator is generally involved in THS lift adjustment under all laws but direct. The way I read the block diagram, when you use trim wheels, the elevators don't do much, so you are moving the THS, but I may be misreading that block diagram. That would explain why those who have used it have to be very careful with trim wheel control of pitch, as the fine pitch trimming, or fine pitch control, via elevator adjustment isn't to hand in that case.
If I have misread the block diagram, my apologies.
Beyond that, any semantic argument about what trim should
mean isn't as important as what you learn in type training, and follow on training, about how your flight control system and auto pilot functions work, in full up modes and in degraded modes.
The first fleet helicopter I flew had a different trim system, and different AFCS, than the second fleet helicopter I flew some years later. Just because the trim systems didn't work identically doesn't mean that I could not trim the aircraft, didn't understand how to, or was somehow at a loss.
You learn to fly your aircraft.
It's what good pilots do.
It's what professional pilots do.
If for one reason or another there is a systemic obstacle to such systems familiarity, that must be addressed.
EDIT: I may be dating myself. AFCS "automatic flight control system" and EFCS "electronic flight control system" (now DFCS??) which abbreviations may no longer be in general usage.