Marc,
I am not a pro but went as well through numerous camera system changes during my whole life, including MF (Hasselblad analog and digital) and Leica including R9DMR - exactly same is true - it did not improve my work/output but just costed me tons of money and many hours of adopting to the new systems - far too much even for a passion.
Having said that in the end I also enjoyed using these different systems, I stuck more with Nikon than Canon but there was no real reason fro that other than my dealer (friend) is mainly a Nikon shop. But I many times lusted after the Canon L glass and the one I used (1.2/85, 2.8/16-35, 2.8/70-200) was just stellar and at least as good as the Nikon pendents. And actually when the 1DX came out I was almost tempted to switch again, finally I stayed with Nikon. And the advantage is meanwhile - hand whatever camera of whatever brand to me and I will be in control of this new beast pretty shortly. Does it improve my photography? NO?
Many times I feel sorry I did not buy back into an M240 for my M glass (which I kept and will keep forever including my analog M's), as the simplicity of this camera (concept) is (and has always been) a relief in our photography times. And actually the new MP digital is very tempting for me - I know this is maybe GAS again, but in my age I may not change anymore, only get slower
I also wish Canon and Nikon good luck for the future, but given their ignorance of mirror less I feel other brands might take over.
So you might go back to Canon? just kidding
Peter