The best way to sum up Common Core is that it is a set of goals.
The good part about Common, shouldn't there be some minimum standard of literacy for all? And I mean literacy in the general sense. You can meet and beat those standards and get there any way you want. You can exceed them. Nobody is telling a district that is where they stop.
When Common Core was fully implemented at the Junior High level with my oldest and we went to curriculum night at the start of the year, The teachers on the team gave the overview of the general math, and for the honors math, they basically said, they're doing something else, no need to concern yourselves if your student is in honors math. Why? They probably were roughly a year or up to two years ahead of the standard curriculum conceptually with some of the topics.
That being said, CSpan is my mass for shut-ins. I have encountered some passionate vocal opposition to Common Core, in one instance in a forum sponsored by the Pioneer Institute I think. It has been a few years. Among the ardent opposition was a woman, retired I think, university English Professor. I think she was involved with earlier standards for language arts in Massachusetts. She bemoaned the fact that the emphasis on endless citation of evidentiary examples in literary analysis at even the most basic elementary level would hamper student's creative thinking and result in too lawyerly or technocratic of a mindset. The professor feared that students would miss out on too much classic literature and a passion of pure reading for pleasure with the increased emphasis on non-fiction reading and writing. Those were among the concerns if I recall correctly.
One of the anti-Core arguments during this broadcast was the fact that they felt that Common Core actually lowered the standards that Massachusetts already had. Except they missed the point that that is a minimum goal.
Another example: Within my school district, we have lots of transferees. Just like military families. Someone moves from out-of-state, expecting that their son or daughter will continue in honors programs here because they did elsewhere. Very often, our district has a rubric that these kids will not qualify for. Why? The totality of our district standards, a rubric of nine components, are set at a higher level.