After reading some of the helpful comments, I'm starting to think that (perhaps) I should try a little harder with my Canon gear. I really haven't dipped my toes too far into the AF configuration (shame on me) and that could improve my success rate for the school sports that I shoot.
As another more-or-less lifelong Nikon user, I'd also be reluctant to advise anyone to switch at great expense, even to Nikon, without being really sure it works for you. Certainly you'd be best served by renting the higher-end Nikon gear to see that it works for you before taking any drastic decisions. Of course, it depends which of those roles / tasks is most critical.
What makes sense for those who have existing large-ish lens collections is different than for those 'starting.'
Plus, some of the difference between platforms is just personal preference. I have _never_ been able to 'get' the handling of Canon cameras, digital or film (FD or EOS). That makes no sense but that's the way it is. You may just not like Nikon digital, whatever the capabilities.
A few additional thoughts:
1) I really, really like being able to use the 'same' lenses on both manual, film autofocus and digital. But the reality is that I don't do it much: generally the simplest and best manual focus stay on the period-appropriate cameras (FE etc), and autofocus on the various autofocus bodies. There are some exceptions (manual lenses that I particularly like will get used on digital or just for fun occasionally), but _for me_ it's not so frequent that I would change a system just to do so.
2) The number of 'special' lenses with no digital equivalent is not so very large - at least for most uses. I find the ones that I do like to use on digital is driven more by my own attachment to a lens (from long personal use) than any real need.
3) Stop-down metering is a very different (and far less painful experience) on a digital camera with auto-ISO and immediate playback than in the film era. I have a few lenses that I have to use this way on Nikon, and I'm surprised at how easy it is. I presume this is same on Canon. While I haven't ever done it, there is an advantage on Canon of being able to use adapted lenses of almost any MF make (if you don't mind the stop-down procedure). Maybe that can satisfy your compulsion to use MF lenses on digital.
That said, there are clear advantages for those with lots of Nikon lenses and bodies. Cameras like the F100 and F4/5/6 bridge the generations exceptionally well, and e.g. the F100 is cheap now. And even though I don't do it much, I love being able to move my AI-adapted 24mm (ancient) from an FM to an FE2 to an F100 and then a d750; that lens has something special (or I think it does, which is the same thing from my perspective). But it would be hard to justify an expensive system switch on the basis of that lens and I few others that I have an attachment to.