and if you ask me, Nikon's lineup seems really good if you're looking to upgrade to full frame:
D4s for professional sports
D810 for studio and landscape
D750 for semi-professional action and wedding and event pros.
D610 for advanced amateurs
Desperation? more like excellent planning for if canon had such lineup many here would be praising their wide selection instead of making stupid comments about how this somehow weakens their system. Many people have asked for this camera and nikon listened which IMO is a quality canon should follow.
Well surely that equates to:-
D4s 1DX for professional sports D810 MIA for studio and landscape (though Canon seem to have been of the opinion that their sensor tech and higher MP in the 135 format are not a market they are interested in) D750 5D MkIII for semi-professional action and wedding and event pros. D610 6D for advanced amateurs
Of course you failed to mention the Df, and that is the one that that has thrown the Nikon FF lineup the curved ball and elicited the smirks and derision it seems to have deserved.
The Df for me is really a camera that fell into fanboy no mans land, hated by the mirrorless crowd for pushing in on "there turf", hated by those pushing the standard DSLR form factor, hated by the Canon fan. Ultimately though I'm guessing its gotten Nikon are fair few sales from people outside these camps and probably didn't cost them a massive amount(new body but no new sensor, AF system etc).
Canon might potentially be able to do without it but today I think even Nikon really needs to go after the niche markets, the key is I'd say to do so in such a way that its cost effective.