Excellent point Curious3!
I'd also like to add that LB and Gershwin offer different musical "palettes" so to speak, at least to my ears, and don't believe that one competes with the other, even choreographically, and they should both flourish.
If anything, from what's been posted here on the Paris show, I believe the 2 shows have the potential of feeding off each other by (thankfully) re-kindling what traditional Broadway musical theater has been so lacking in for years.
What An American In Paris has in its favor will be the curiousity of its "originality", a brand new Gershwin Broadway musical with all the "goodies", created from one of the most recognized musical compositions, and movies, of our lifetime.
Curious3, brilliant minds think alike!