Methods: Does failing at intermolecular properties mean the same for intramolecular properties?
I think the distinction that you are trying to draw is (as you have hinted) better expressed in terms of covalent and noncovalent interactions, rather than inter- versus intramolecular interactions. A technique that fails to correctly describe noncovalent interactions will fail whether or not these interactions are between two moieties on the same molecule, or on different molecules. The usefulness of a technique that fails noncovalent interactions is contingent on whether or not those interactions are significant to the particular properties of a molecule that you are investigating.