1. No matter when you buy a camera, it's a near certainty that something even better will be released later.
2. But it seems reasonable to believe that the closer you are to the most recent FF releases, the further you are from the next one.
3. So unless there's some reason to believe that Canon will change its schedule other than wishful thinking, now seems a good time to buy one.
4. (And unless you need to photograph things moving about fairly rapidly, I would have thought a 6D was sufficient - the images it creates are at least as good as (some say slightly better than) the 5DIII's.)
5. On the other hand, if you're patient you may want to wait until later in the year in case the 7DII contains miraculous advances that somehow make it more attractive than a 6D or 5DIII
6. A used/refurbished 5DII is better than what you currently have and it doesn't seem likely that their price will go down much within a year or so; so you could buy one now and, when the 7DII comes out, buy whichever of the 7DII, 6D or 5DIII seems more appealing at the time.
7. Meanwhile, if this is an option wherever you are, you could rent a 6D and/or 5DIII, compare them to each other and what you presently have, and ponder whether they have any shortcomings that matter to you and that seem likely to be addressed by an upgrade. You could also throw in a D600 to the mix and discover whether potentially superior shadow recovery is something you would ever benefit from (you may conclude, as I did, that any differences in that regard between a 6D and D600 are trivial).