With both the r62 and the 5d, the one huge bugaboo for me is...vertical video shooting. There no record button on the grip...why? Because that wasn't the usage intent when it was designed. It likely just followed the tried and true formula (ie. no one needs vertical video...although everyone's on phones...yup).
90% of my video clips is in vertical format, targeted at social media formats. While the later r62 seem more suited for this scenario software-wise (maybe, already forgetting), the grip is definitely not taking that scenario into account.
Yes, just set a button! Unfortunately i would have to change the buttons on the body as well. It can be done, just better if there was an appropriately placed, red, rec button that was easy to access. I waste a lot of time clicking the rec button and then setting my hands, then try to stabilize.
We'll see what happens with the updated versions. Chances are it will take a long time to get 3rd party versions, and canon could try to lock some out like they do with batteries.