IMO there is much knotting in the SPart for dubious benefit,
and way too little of the Returning Eye Leg's part in finishing
the knot for serious/critical use --use where "stuff happens"
is a consideration. (I know of plenty of eye knots where the
SPart does wonderful sure-gripping stuff, but I still worry that
the SH consideration must guide one to a greater involvement
by the RELeg-Tail piece!
Not so dubius benefit, i believe, if you consider this blimp
"much knotted" structure, as a non-jamming stopper knot, which, IMO, is a great aspect.
Things change a bit, when one of the ends is designated as the SPart for eyeknot development, but think of the two overhands, as two combined closed forms sharing a common line (bridge) that is being nipped by both SPs shear forces (zeppelin property).
Considering, also, that the on going tension is smoothed and absorbed by the on going collar, (see the difference with the zeppelin loop where there is more straightforward, nipping, on going action, which at some point, is going to jam the overhand nipping component), the two overhands cinch only from one end, while the other one (the bridge) is almost deactivated.
With respect to "stuff happen " situations, i have included a gradual returning structure involvement, by inserting returning toggles/hinges, from straight line to loop.
I could certainly add more returning knotting, even a tail stopper, but since it works, i prefer to keep it in the simplest level!
I clearly see your point of pushing the complexity to the returning level, but this is a reverse scenario that actually works.