Dear Derek2: First of all, best of luck in becoming a producer. I believe that the success of a good production of the Wizard Of Oz (hopefully yours) would depend greatly on timing.
Let's say you open in a season when Beauty and the Beast has closed, Disney has no major familiy show and Wicked has ceased to be a sold-out affair. Maybe you could then capture all those family audiences and make a buck. If however, you open in the same year when, say Disney opens "Little Mermaid" or "Mary Poppins" and you have B&B and Lion King plus Wicked against you, it would be hard for your show to make a profit, especially since it is bound to be a very expensive production.
I did see the US Touring show and thought it was good, although the Munchkin scene always is hard to stage because we all expect to see hundreds of little people, not a dozen kids or adults in trick costumes. There was also the Madison Square Garden production with Mickey Rooney as the Wizard, listen to the CD to maybe get some ideas of how a stage version would sound.
The meat is always leaner on somebody else's dinner plate!