That said, I think think both maps side by side would be great. They complement each other for being good for different things.
The new metro "diagram" that tries to to clearly show information about how the routes work, without being geographically accurate.
The new map that is geographically accurate, but less detailed with respect to the routes, but also shows selected bus stations.
Optionally, in lower Manhattan, a third geographic map that for lower Manhattan blown up to the be the same size as the others (and allowing more detail). A smaller blown-up version is included in in the main geographical map as an inset, with greater detail, but perhaps not as much as the fully sized version? Unclear.
* the modern Vignelli (thankfully) fixes some of the 1972's version issues with things taken from the current map; namely, most of the glaring geographic issues have been fixed (50th/8th is not in the wrong place in the grid compared to 50th/7th, Broadway is now a diagonal line instead of a stair-stepping line at 90 degree angles); and the new map uses the same common-trunk coloring scheme that uses 9 colors as opposed to 1972's one color per distinct service (for something like 25+ colors).