I have grown up with the 1D series bodies......1DMK2n, 1D3, 1D4, now the 1Dx and also have the 7D2
And....I shoot mostly motorsports as my primary..and wildlife secondary
Comparing the 1D4 to the 7D2........85% of the time...I wish I had it back....here are my thoughts to that:
First....the 1D4 AF is still better at grabbing and maintaining AF
The ability to determine focus is more consistent (to me)
The 1.3 crop produces some solid images that I don't have to massage
ISO comparison....I'd still give a very slight advantage to the 1D4 (to me)
Now...why did I take up the 7D2....mostly for the extra "reach" of the FOV from being a 1.6 crop.
Second....the viewfinder view...is like the 1Dx...and I figured that my "mind" would work easier since both look the same in the viewfinder
What I feel are let downs.....
Using off center focal points don't give consistent sharpness/locked focus like the 1D4
Tends to need slightly higher shutter speeds to get consistently sharp images than that of the 1D4
You still can't beat the battery life of at 1D series battery...even with a grip on the 7D2 using two batteries
I'm at the point that I'll most likely save up and try to find a mint 1D4 on the used market...keep the 7D2 as backup and
extra reach use.