I think the main problem is that Pantera WERE Dime and Vinnie. In so many bands, members are replaceable and the band are still considered 'the band'. Look at Megadeth. Dave is Megadeth and for their fans the only irreplaceable member.
We can all list bands that would be over for us, if a certain member or members left. For the majority of the fanbase (although maybe I'm wildly off base) Dime and Vinnie are irreplaceable. Any version of the band without them is not Pantera. That is my personal view, and I suppose it is something people are vocal about because they are billing themselves as Pantera.
Call yourself a tribute to, or whatever, but to say this IS Pantera, feels disrespectful to Dime and Vinnie. As to whether Dime and Vinnie would be cool with it? Vinnie was very vocal over the years, stating there was no Pantera without Dime (and I agree). Dime was a lot more chill and was just always up for a good time, so I believe he'd actually probably be fine with it. It just seemed like the sort of person he was.
It unfortunately seems like a money making machine, and as much as I would like to see Pantera live, and this is the closest I'd ever get, I can't help thinking I'd be left feeling shortchanged.