Edmund,
Gear is like mind...you know it.
A very good slave but the worst master you can have.
As mind can litterally dominates one's life and take whatever "decisions" where the self has no control, (unless you end to dominate your mind),
gear works exactly the same way. It's possible to dominate the mind because the mind is only a tool, same as camera. If you don't do it, they will dominate you and drive you anywhere except where you really want to go.
In this case, the decision is the output you have in mind.
The very little moment you start to think about sensor, AF or whatever, especially when you feel that "something is missing", at that precise moment you just lost your own creativity power because you give your energy, time and attention on things that have very little to do with good imagery.
I hear a lot people saying with some kind of "modesty": I'm not talented, I'm not creative. But then, you look at their discurses and yeah...everything makes sense. It's not that they aren't talented, it's that they are trapped into something that inhibates their talent, and generally it has to do with "easy".
Something easy is not worth trying.
For ex: it's much more easy getting a 60000 bucks camera and shot brickwalls than acheiving top imagery with a 500 dollars camera. The same, it's easier to shot D3 than Leica M.
When you say that you always get the shot with the Nikon, are the shot worth? If not, that's ecual than saying: I always get the crappy onces with the Nikon...as drastic as it sounds.
Just try this Edmund, even if you don't beleive in it, just try this for 15 days and then, come back on that topic and comment on your results.
1- for 15 days you decide that there is no specs of your gear that is missing or not working the way you want. That's not your concern.
2- for 15 days you oblige yourself NOT participating to any technical discussion, not reading any line anywhere, not contaminating yourself with anything that has to do with cameras, specially, very specially the things that you see as "limitations".
3- Transform the word "limitation" by this one: "adaptation"
4- for 15 days you decide that the only thing you are going to explore is your own creativity, lenguage and personal style. If during those days you experience "failures because of the camera", transform that in "failure because of me".
5- for 15 days your only concern is going to be acheiving a precise imagery you have in mind, and as you have eradicated the words "gear" and "limitations", your only concern is to find a way to acheive this goal.
6- for 15 days you decide to coahabitate with something that, like humans, is not perfect, and your only concern will be to extract the best of it without judging or comparing the cameras you have or the ones you don't have, and specially not giving any credit on the ones you'd like to have. It would be even better you oblige yourself not using AF.
7- then, for this period of time, you are going to watch a lot the great masters you admire, it's easy in Paris, watch the pics and draw your own conclusion about the importance of certain concept. In other words, what do you priorise? What do you really understand by getting the shot seeing the masters? Does resolution is your concern? Do you feel unhappy when you see your pics at 100% on the dev? Why?
If you do this little game, I'd really like to hear from you after those 15 days. You might be surprised.
Remember: tech calls tech. Gear calls gear. and frustration calls...well you know.