Hi Nazareth, quite honestly sorry to hear the issues your having with with the 1Dx, not helpful of course but I had both my own 1Dx bodies into Canon Singapore last year & both returned just fine.
I do appreciate threads like this, the heads up warnings at least allow us to understand that there are often issues out there with the equipment we use.
If you wouldn't mind I'de like to know which Canon service centre you put your 1Dx into, only so I don't make the same mistake myself should I ever again have the need to service/repair a unit other than through Canon Singapore.
Among the comments made by Nuero there is one Gem and I was unaware of it myself, that's the comment regards use of a Credit Card with Amazon extending the Warranty Period, I've checked the info and it appears correct, this is useful information for you (and anyone else) in the hope that your Camera may still be under Warranty, worth checking.
You have my sympathies, for most a 1Dx is a significant investment and it's a little world shattering when things go wrong, your "little rant" is not unusual & your endeavours to give a heads up over an issue I at least was unaware of, should be commended.
My own history with Canon/Nikon might put some perspective into the problem, I owned the 1Ds MK III, This had been a total Horror story with the well documented AF issues, 5DMK III light leak issues on 2 out of 3 Bodies, D800 left/right out of whack Focus issues, Nikon finally replaced the Camera Body & I promptly sold it, My 200f/2 300f/2.8 II 400f/2.8 II 600f/4 II all required sending back to Canon Singapore for new firmware due to upgrades required due to release of the 1Dx & 5DMK III, so one might ask "why stay with Canon" ?? I understand these issues are relevant to all Camera systems & Canon I feel generally provide the best after sales service.
Don't take to heart negativity on a public forum, it's part of the beast, take the positives from the experience, hopefully there are some, i.e.. the extended warranty via Credit Card payment at Amazon.
I hope you get the issue fixed, unfortunately it's likely made you a D4s future buyer, but believe me all the Camera Manufactures have the same issues, these are mechanical pieces of gear, just like a Car or a Toaster, most work out of the Box, some don't, you unfortunately got one that has issues.