I'm intrigued by your footnote comment re a left-shoulder pass's being a
"technical flaw," and would be happy to have you elaborate.
I myself have found, for example, the following:
Mairi's Wedding done in a crowded ballroom situation with left-shoulder
passes is awkward and even sometimes results in collisions; the right-shoulder
pass, even though it's more fun to do with lots of space, is also much more
"do-able" than the left under crowded conditions.
When doing The Maze the original (not deviser-revised) way, it's virtually
necessary to pass "wide" (right) between half reels in order to have the
impetus to cross the set after the second half reel.
I have done Irish Rover with a short (left) pass between half reels as long
as I've been dancing (and ASSUME that it's written thus), but just recently
visiting a class in Australia was instructed (along with the rest of the class of
course) to pass right; "when in Rome..." and so I did, and found it to be no
worse and very possibly better in terms of the flow of the dance.
Perhaps--and this is the first time that it has occurred to me generally as
such--a short (left-shoulder) pass between half reels is just a bad idea
altogether, as Bert seems perhaps to have suggested.