I think it could be a wonderful popcorn movie. Especially if they film on location.
Here are some of my ideas for casting:
Donna- Olivia Newton John
Sam- Travolta (if he loses weight- much better fit here than in HAIRSPRAY)- and how fun to see these 2 together again?
Tanya- Stockard Channing in full Joanna Lumley mode (I wish they would cast Mary Ellen Mahoney but a girl can dream)
Bill- Richard Gere or Tom Wopat or Treat William
Harry- David Cassidy
Can't think of anyone for Rosie right now.
I just think it would be really cool to see people who were in musicals in the 70s to do it.
As for Sophie and Sky- maybe Kristin Bell and the cute guy who is Sharpay's brother in HIGH SCHOOL MUSICAL
Any other thoughts?
Bad Jazz Singing- The Agony of Defeatism, The Thrill of It All