I think the question of how students handle kids with disabilities, is an incredibly important one. When I started teaching, in the city I live in, kids with disabilities were exempted from everything. I can tell you so many stories of students of mine who spent their days before they got to me coloring, or cutting and pasting, or generally being ignored. Kids shut down from that too, because kids need stimulation and challenge. On the other hand, in those days as a special educator, I had enormous freedom in what and how I taught. Very little was dictated to me, and so I could tailor my instruction to exactly what kids need.
Then NCLB came along and the pendulum swung the other way. Suddenly, the only thing that mattered was "grade level standards". If third grade was multiplication, and you had a child who couldn't count, well they worked on multiplication anyway. The other day, I was asked to consult on an IEP from a student not at our school. This was a high schooler who was working on very basic level math. During testing, he needed to count out manipulatives to add two numbers under 10. But his IEP was full of crazy stuff like "given a page of algebraic problems, will circle the ones that show the distributive property". This was a kid who needed to learn how to count money, not to identify properties of algebra problems he couldn't solve.
Figuring out the middle ground is going to be crucial, whatever the standards. While, for some kids, the old standards might have been accessible while the CC one aren't, that's a very small slice of kids. There are also plenty of kids for whom neither are accessible, and other kids with disabilities who will be able to reach the new standards too with the right structure and support. With or without the CC standards, states need to figure out how to handle students who need substantially modified curriculum and expectations, because right now there are too many heartbreaking stories.
However, the solution isn't to lower the standards to the level of students with disabilities. It's to figure out ways to bring as many students with disabilities up to the level of the standards as possible, and to develop systems for modifying standards when appropriate.