If we accept these six key attributes of Wrangler success:
-- low entry price
-- removable roof and doors
-- appeal to youthful customers
-- support by aftermarket accessory companies
-- "adventurous" image
-- actual off-road capability
I think Jeep could build a lighter weight, more economical new Wrangler with IFS and meet all six of these criteria. Jeep would need to hire folks like Scott Brady to show that the new model has off-road chops similar to the old SFA model, at least in stock form.
No doubt, the aftermarket companies that produce Ford 9 inch axles and V8 adapter kits for JKs would have to go back to the drawing board. But I think a large group of current Wrangler owners could be convinced to buy the new product.
Chrysler doesn't really manufacture the Wrangler. They build it from sub-assemblies provided by three independent suppliers with operations in the Toledo Supplier Park. Jeep could cut a deal with these companies to continue the production of the current JK for a couple of years, while the skeptics are won over.