"Well it depends. Criticism of the form "make everything look as I'm used to" is not very interesting."
It may be not very interesting, but that's a valid criticism nonetheless: 'This worked for me and you changed it in such a way that it doesn't work as well anymore, why is that?' So far no answer to this question.
"The people behind Gnome 3 decided to innovate, adopt a new interface and go on. That's a difficult decision for an established desktop but nevertheless they did. Irrespective of whether I like the new desktop or not, it is nice for free software to innovate and include new designs."
The problem is, the end result of their attempt to innovate has proved to be less effective than what already existed for quite a number of users. Worse, so far we still don't know how what we had was broken and why it needed to be fixed. Seems that we should learn to love the "brand", yay! :)
"Btw. I think most of the gnome 3 criticism comes from the fact that the new interface requires some introduction (10min one) on how to use. Maybe they should ask the age of the should have included a video played on the first installation. I'm really old-school person but liked the interface only by the time I watched a video in youtube on how to use it."
That's actually a good point, but you shouldn't assume that most if not all of the criticism comes from people who tried GNOME 3 for less than 10 minutes: I was an enthusiast, I followed discussions about Gnome 3, and I tried to like it. The fact that they failed to impress people who were loyal users and supporters should speak volumes to anybody.