If you don't know which way to go, then pick up a couple 5D3's or a 5D3 and 1Dx -- then build your glass. I'm not trying to be flippant, but the time to upgrade is when you find that you are frequently pushing the limits of your current gear. If the 5D3 was fine for you, then you may not be pushing it's limits enough to warrant the 5D4 or the 1Dx2.
In my case, I shoot a lot of action in low light. When my 60D wasn't keeping up with focus tracking, I upgraded to the 7D. When I found that I was constantly cleaning the noise from high-ISO images from the 7D, I upgraded to the 5D3. And, when the 5D3 still had trouble locking on to figure skaters performing double jumps during ice shows, I added the 1Dx. My keeper rate increased with each of these upgrades. Still, I find that I'm often flirting with the limits of the 1Dx and someday hope to add a 1Dx2.
It's hard to offer advice without fully understanding what you shoot, how often, and what you demand from your gear. My 1Dx is my primary body. But, I most often shoot with two bodies and often shoot events where the 1Dx shutter noise can be an annoyance. Consequently, I've kept my two 5D3's. This is why I'm suggesting a 1Dx and a 5D3 -- you'll have sports covered, have two bodies, and have the silent shutter for the occasional wedding.
On last note. While photography is all about the image, part of the fun can be found in the gear that you use. I don't always "need" my 1Dx for every shoot, but it does have a fun factor that's hard to resist. So, while a 1Dx and a 5D3 may be practical advice, they may not have the same fun factor of their successors. In which case, go with the 1Dx2.
