Just small incremental upgrades. Not much to show for all the years of development if you ask me. I'll skip the mark II, thank you.
I'm really torn. One group that I talk to is saying that the 70D was only a marginal upgrade over the T2i (that I currently use). They're also saying the 7Dii is going to probably only be a marginal upgrade as well. I bought the T2i years ago when I was first learning how to shoot. But there's a lot of people on this forum saying the image quality would be massively improved over the T2i if I switched to the ii.
I'm photographing mainly wildlife, about 85% of what I photograph is birds, smallish ones. In actuality I'm only using the center focus point probably 90% of the time as well, since I'm good at getting in the range of my 400mm, and it's close enough that the center point covers most of the bird.
May skip the ii, and maybe go to a 5diii or 6d or something, since I'm not hurting for reach in the least.
The truth is usually somewhere in the middle. You will see an improvement in image quality with the 70D, it will definitely be noticeable, but it will not be earthshaking.... but the user interface is drastically different and according to those who have gotten used to it, much better.
As far as AF goes, yes, the 70D has far better autofocus, but if you just use the center point you will miss most of the advantages. What you will see is that the AF on that center point is more accurate and of course, if you go into live view, the DPAF is a huge improvement..
As far as the 7D2, nobody knows..... until people get their hands on it, you are just hearing guesses and opinions based on rumours and startlingly devoid of facts.