Duffer2007
I know nothing about the Seneca stalling characteristics however I know a great deal about the airflow round the Seminole wing at the stall as I used to use one suitably tufted to teach such matters to Uni students in the 80s.
You ask for a simple answer as to what is going on with the Seneca. Therein lies the catch.
How a wing stalls is not a simple matter and depends on a combination of features and I would suggest the main ones are:
Aerofoil choice AND how this changes along the span.
Planform shape and aspect ratio.
Twist.
Presence of any fixed leading edge devices.
In the case of the Semiole as an example if you stand at the wingtip and look towards the root you will see :
An aerofoil that changes markedly from the root to the tip (and even includes a bit of LE droop near the tip)
A wing that has considerable twist
To me this wing just screams experience and extensive flight development on this or some other related design. It exhibits really classic root stall characteristics, ailerons that work well deep in the stall and stacks of natural warning. In short a GA dream. But there ain’t no simple reason for this!
JF