As good as the D3X 'was' - you're bing overly sentimental about it. The D800/E is a better camera in terms of quality output. It's also rugged enough in it's own right. I don't know many who 'actually' need the security of the bigger pro bodies. Unless you cral through rocks and mud when shooting often?
Anyway, this lens has been tested on the D800 and got better scores for it, the overall lens database needs updating.