There will never be another Walt, no, but I also don't think that it's accurate to say that he was a lone figure who just did whatever he wanted unchecked all the time. Walt was a part of a Eisner/Wells style relationship with Roy.
Walt gets all the credit, but Disneyland, and indeed the company as a whole, would've never become what it did if it was Walt alone. Walt was a genius in many ways, but he was also a fool in other ways. He had brilliant ideas, and he had really terrible ones. Thankfully for him, there was always someone there to keep him from doing too many dumb things, and helping him to do his brilliant things in a way that didn't completely destroy him.
To that extent, I agree with you that a duo would be the best case, because that's been when the company has been at it's best. Never has the company completely thrived under totally centralized leadership. There was not completely centralized leadership when Walt was alive. Everyone points to him as the says all ends all, but Roy was right there keeping him balanced and I think deserves just as much of the credit for the Disney we know today.