I really don't know how this would work out.
Someone on the Dylan forum said that if the Bob&Mark tour happens, it will probably be a hit parade, which will probably be the most commercially reasonable solution if the general audience / casual fans are the target. But would the artists be happy and interested in this?
The Dylan purists and Knopfler nutters clearly want their artist to themselves, so, is a double-header tour with two distinct parts of the show an option? The general audience want Blowin in the wind and Money for nothing, which drives the puristst in either camp crazy, and possibly also the artists. The purists want the obscure "special interest" stuff, which will alienate the masses and possibly further increase the division between them.
If only Bob&Mark had had a joint project prior to the tour and there would have been some "hype" a la "two masters together for the first time in 25 years", then it would make sense. Otherwise, I'm still very skeptical.