Or if you have no iPad.. But I agree, I'd be thinking hard about not upgrading if I already got an Air 2, but then, that's why I and others held out for the latest model.
Performance wise I can't comment on the iPad Air 2 vs. iPad Pro 9.7" because I haven't used the former in real world use enough, if at all, however I would be extremely surprised if "performance wise, it behaves and stutters exactly like Air 2 at the exact same places". Can you give actual examples of that? The benchmarks are what I've reviewed, and performance wise, the iPad Pro 9.7" is clearly superior with a faster chip, x2 generations removed from it.
However a lot is made of the RAM being only 2GB. Sure, 3 or even 4GB would be nice, or even preferable, to keep the RAM fans appeased, "hey, it's got 4GB RAM, check out my package".. but Apple is being Apple here. They have done what they do, and developed a chip to work with their OS in an optimal way. For them, it doesn't 'need' the extra RAM to run the OS, and run things smoothly. I've used my pro in split screen, played intensive games on it like Assassin's Creed, and it's great so far. The benchmarks sort of support this as they're comfortably close to the iPad Pro 12.9" which they obviously deem 'needs' the RAM boost owing to all the extra pixels being push on the larger screen size.
If the situation changed where the OS changed significantly to 'need' more RAM then this is the point people would have cause to bemoan lack of 4GB RAM in an iPad Pro 9.7" in my opinion.