There are fly patterns such as the 'Waterwisp' that are tied in reverse with the hook eye at the tail. It would be easy enough to tie up some examples and fish them side by side with a conventional pattern to see if it made a difference. My guess is the fish don't care much about the wing presentation as much as they do about drag.

For my money's worth the strike triggers (or lack of strike if you get them wrong) in order of importance are:

1. Stealth - if the fish see you you have lost have the battle. Slap a cast hard on the water and it's game over for a while.
2. Natural Movement, this = drift for a dry fly. Any micro drag alerts fish to an impostor.
3. Profile - the outline and overall shape. Fat body vs thin body, upright wing vs spent wing, float low vs float high, legs vs no legs.
4. Size - some times changing to a smaller or larger fly makes all the difference.
5. Color - some times just the right shade counts, olive grey vs olive. Sometimes an attractor color works (red, orange or some flash)

then way down on the list...

23. Fly facing upstream or downstream. Not to be confused with 'right side up vs upside down' (ruins profile) or 'Moves upstream vs down stream' (ruins natural movement)