I wouldnt say the 1DX is better in every way. Some things to consider against the 1DX
1. Cost - You can buy two or three 5D3's for the cost of one
2. Size - No removable grip so you have to lug the heavy camera everywhere...plus the charger which weighs as much as the camera
3. Noise - The shutter is very noisy. Even in single shot it will turn heads. In drive mode it's a machine gun going off. Scared off a lot of ducks with that one.
4. Shorter battery life - 5d3 with one battery will last longer than the 1DX. Add the grip to the 5D3 and you may last a week of pretty heavy shooting before needing to charge batteries.
5. 1DX cannot run Magic lantern. 5D3 can, adding a lot of additional capability such as one shot HDR (Dual ISO), focus peaking, intervalometer, ETTR and more.
6. 1DX is 18MP. Not much smaller than the 5d3's but if you end up cropping you will notice it.
I opted for the 5D3 and have used that for pretty much everything from landscapes to pro sports...now that I have the 7D mark II, I also have the FPS and AF system to help in that regard. Oh and between the two I spent less than that of one 1DX.
1. Yes the 1DX is expensive. But 2 or 3 5D3's - err no, well not in Europe anyway! Not even 2.
2. Yes it's heavy - I agree. But a removable grip makes any (non 1 series) very wobbly on a tripod. The charger is heavy but I bought a non OEM one that weights next to nothing, works off mains voltage or a car cigar lighter (comes with adapters/leads for both) for 18 GBP (about $29) and included a LP-E4 battery that works just fine in 1D3/1D4/1DS3 and 1DX.
3. Yes the 1DX is noisy, I shoot mainly wildlife at close ranges, why do they completely ignore me?
4. I assume that comment was a joke.
5. I Cannot comment as I have yet to find a use for those features.
6. Again I assume you are having a giggle - try it for yourself. I have and no it is not the case.
The 5D3 is an excellent camera and, for many a better option than the 1DX, but that in no way makes the 5D3 an equivalent camera. I was a little surprised at you post as, previously, I found your insights to be useful and constructive.
However for the OP's requirements I agree the 5D3 would appear to be a better option IMO.