Eggg Zaktly!
given the choice of a darker viewfinder with a constant f/4 lens in that focal length or a similarly priced f/2.8 lens with the added bonus of the ability to shoot 1 stop faster to boot!.. I'd prefer the 300g extra weight of the f/2.8 lens.
Nikon stopped producing 70-200mm f/4 lenses very early on in their history, and probably saw no reason to re-introduce them again.
For the type of photographer that needs AF-S in this type of lens because of the limitation in their existing bodies(D40's, 60's 3000's and 5000's and so forth), I think the $1.5K price tag of a 70-200/4 lens may be a bit steep anyhow.. so the current(and very good) 70-300VR lens maybe a better half priced alternative!
I think a better bet for such a lens type for Nikon to produce/upgrade would be to add VR to the current 80-200/2.8 lens, and maintain a price point at less than $1.5K.