I can agree with the tooling aspect but everything else can be accommodated quite easily. Hell even tooling really isn't such a problem. They retool on major redesigns anyway, just consider it a major redesign and get on with it.
I'm just getting tired of badge engineering.
That's an entirely different animal. What you actually want is the same treatment that the Challenger got.
The big hurdle is design costs. Developing a new platform today-and keep in mind, a platform is just a set of dimensions that can accommodate many completely different vehicles-requires that platform to sell around 150,000 units a year for the first few years to remain profitable.
There are two exceptions-platforms that have a few decades of continuous evolution under their belt (Like the Wrangler), and those that are exceptionally specialized and sold for a much higher price (Like the Viper).
The Grand Wagonner doesn't fall under either category. It HAS to share a platform to remain profitable.
That said, most people don't understand how diverse a platform actually is. For example, most people know that the Chrysler JS platform underpins the 200 and Avenger, but it's also the basis of the Journey too. Ford's D3 platform underpins the Ford Taurus, Edge, Explorer and Flex. The new Chrysler/Fiat C-Wide platform will underpin everything from the Dodge Dart to the Liberty replacement, a number of new Alfa Romeo and Lancia small and midsize cars and CUVs and possibly a Maserati.
Platforms are completely separate from parts-but they do lay out the dimensions those parts require.
To build a new BOF Grand Wagoneer platform would require one of two things. They'd either need to design a new BOF platform, and find a way to spread it out over several model lines (Like the old SJs) to amortize development costs, or they'd need to adapt either a Ram platform or the Wrangler platform. However, the Grand Wagoneer is meant to compete against much more luxurious vehicles, and those platforms lack the necessary refinement for what the Grand Wagoneer was last specced at.
That said, there is some speculation that the Grand Wagoneer might wind up in one of those and come downmarket a little bit-aiming more at the Suburban and friends.
But building a 'new' Grand Wagoneer, built BOF and modeled after the original with new powertrains, is an economically impossible proposition.