It will be easier if I approach CCSS with a list rather than trying to organize all thoughts at once. So don't expect this to be a thorough well-rounded view.
I'm not excited about CCSS because I'm not excited about national or state anything when it comes to education. Any time some bureaucrat in an office hundreds/thousands of miles away wants to tell me best way to teach the student who's sitting six feet away from me, I'm not interested. You aren't here, and you aren't a teacher. You don't know. And the fact that you don't know that you don't know just further convinces me that you really, truly don't know.
I get the appeal of standardization, of lining up all the ducks in one big efficient row. But there's one thing you must have for Central Planning For Everyone to work-- you have to have somebody at the center of things who knows what to do. If you're going to get everyone in line behind One Right Answer, then somebody has to be able to reliable provide One Right Answer every time.
That person does not exist. Central Planning fails. It always fails. And it always fails because it creates a brittle, non-robust system that wastes energy making people line up behind an answer that is often wrong, because nobody can be right all the time.
Read chaos theory. Read information theory. What we know is that the one "right" answer always emerges and fights its way through a sea of many and varied answers, and you have to have that sea of chaos for the right answer to emerge.
It's seductive to think, "Can't we just skip all the wasted wrong answers and go straight to the right one." The short answer is, "No, we can't."
Edison famously observed that he got the right light bulb by eliminating all the wrong ones. He couldn't skip the process.
The same philosophy would lead us to conclude that since only a couple of games really decided the NFL championship last year, this year we should only play those games that matter. Which is, of course, impossible.
Central planning will always fail. Central planning by people who aren't experts in the field will certainly fail (no, despite what you've been told, no teachers helped write the CCSS). Central planning for a process which involves millions of distinct individuals, each with distinct and specific needs, weaknesses and strengths will extra-super for-sure fail.
Note: Yes, I know that one of the S's is supposed to stand for "State" and thereby help the fiction that CCSS is not a national standard, but that IS a fiction. CCSS is federal-level central planning.