If you shoot in RAW capture mode, it should be easy to correct color balance, in a non-destructive environment. Surely this would make the D810A suitable for all purpose photography. (For shooters who cannot afford a camera strictly for astrophotography.)
You are cautioned not to leap to such a conclusion. There are very good reasons why the cameras have IR-block filters, rather than relying on post-process adjustments.
In general, correcting color balance isn't that simple. More often than not, you can obtain an acceptable result, but there are certainly exceptions where not all of the hues can be recovered.
In daylight, you might be fairly safe, but under warm lighting such as incandescent, expect some difficult problems. I own the 60Da and have experimented with it for general photography, but found the red color shift to be very obvious; I would not use it even for casual photography. The D810A may have even higher sensitivity to far red than the 60Da.
An IR-block filter such as the X-Nite CC1 will work much better than color adjustment in post.