With proper post processing, the impact of a properly designed OLPF (one that blurs out spatial frequencies above the Nyquist limit of the sensor but not below) is minimal. Basically, images from a sensor with an AA filter can be sharpened to a greater degree without detriment than images from a sensor without an AA filter. So while there's a perceptible difference in resolution between the D800 and the D800E on comparison tests (where sharpening is usually not applied at all, or if it is, it's applied identically), you can (and should) apply more sharpening to the D800 output, and when you do, the resulting sharpness will not be significantly different.

OTOH, while you can sharpen an image quite easily and effectively, removing moiré is neither easy nor effective (post processing moiré filters remove the color component of the artifact, but the moiré itself remains in the image).