What is it that makes you want to make the change to Canon with the 6DII from the D750?
For most it is a big decision to change manufacturers, and many do it for big increases in performance or features, but I can't see anything, from my point my view obviously, 
to make such a big change. It may be a lot of minor improvements, but I don't see anything groundbreaking in this release. What is it that makes you want to make the change to Canon with the 6DII from the D750?
What is it that makes you want to make the change to Canon with the 6DII from the D750?
I'd wait for proper tests and reviews before making the jump back tbh. It could still be a backwards step rather than a side step.
No problem with that as long as people are truthful with themselves, and don't discredit a brand they dislike, or embellish the features of a product to in some way justify a choice.
Obviously feeling comfortable with the camera is a very important aspect. Some people can live with a lot of compromises for that feeling of comfort. I stuck with the Nikon D300S for many years because I didn't feel that Nikon had made a good enough camera for me to replace it with their D7*** series of cameras. The technology got so behind though that I was about to buy a 7DII when Nikon announced the D500.
Manufacturer change averted. Even after a just over a year though, the D500, ergonomically, doesn't feel as good as the D300S in the hand. That may not be the case this time.
If you have the money though, who cares. Hopefully there will be the information about by then to confirm it is a good decision.
But I wouldn't make such a big change too quickly without the reviews and user experiences to see if the flaws are fixed. But again, if you have enough money, do what you want, when you want. 
5d3 is a bargain it you bought it at launched and used it extensively for 4 years
It depends what you want. I never needed the better AF and features of the 5D3. I also didn't want it's extra size, weight and cost. For travel and landscapes the 6D is great. The 2 will be better, in particular even better IQ and the tilting screen. At the same price I'd get the 6D2, some significant useful improvements over the original along with my same reasons for getting a 6D in the first place.
Compared to US pricing.... Remember that (1) advertised US prices don't include sales tax, and (2) US retailers don't milk the must-have-it-now brigade as efficiently as UK retailers do. So we all expect the price to fall from £1999 in 3-6 months time, but the US price will probably stick at $1999. Excluding VAT and sales tax, the price difference is currently only about 10%, and that will certainly be eroded over time.
It is to get people like you, who may have wider aperture lenses (and so more expensive
) to buy the higher camera in their range. They think if you are spending a lot on lenses you will buy a camera to as not to compromise them in bright situations. Nikon do it too with the D610 and D750.It is to get people like you, who may have wider aperture lenses (and so more expensive
I said that about the D750, but I haven't really found the shutter speed limiting tbh. At the end of the day it's no different to the very well regarded D700. Whilst that had a shutter of 1/8000, base ISO was 200, so no different exposure wise compared with the D750 at 100 and 1/4000. Plus you have these low ISO modes now with negligible difference in IQ. Granted a 1/8000 shutter would still be nice, but they have to compromise somewhere to make these cameras smaller, lighter and cheaper. It shouldn't be a deal breaker imo but obviously YMMV.
I shoot bees at 1/200-1/250
