HC:
I think you have given a pretty good summary of autopilot differences however I would make the following corrections:
The L2 autopilot is aware of the TQ limit (or at least of the First Limit Indicator limit) and will NOT pull above the maximum continuous torque limit. There is anecdotal evidence of transient overshoots in turbulent conditions (which is maybe what you are alluding to) however I have not actually spoken to anyone who has had a torque exceedance due to this (maybe someone will correct me).
However what you say with regards to using the autopilot at high power settings still remains true. It’s uncomfortable in this configuration, leads to an unstable aircraft and should be avoided.
Having said all that the 4 axis autopilot does actually perform very well on IFR approaches and especially if used in conjunction with an altitude acquire (and the availability of a go-around mode) makes for a stable, controlled and safe approach.
My main point here is that your last statement is certainly not true when it comes to IFR approaches and as far as I am concerned (and the company I fly for):
A 4-axis approach (in conjunction with an altitude acquire for non-precision approaches) is very much the norm on the L2!