If the Landing tries to be too many things to too many people, it will lose its original focus, which was retail. It makes more $$$ as a retail destination, look at all the shop centers that were setup to focus on "Ghost Tours", or "african-american exhibits", they all went bust there, and so will this "museum".
If you really want to drive people into a museum mode, why not look to use the Snyder Church, which is tied to the historical tours of City Hall? You have Chamblin's bookstore close, as well as MOCA and could really turn that area into more of a historical area.
No one knows if the old library will ever open up, so scratch that as it sits empty. I go to the Landing for the restaurants, just like I go to MOSH for the history. Would I ever go to MOSH for lunch? Of course not, so don't ruin the Landing and turn it into something its not.