Content standards like Common Core are written curriculum. Written curriculum is always a work in progress and always up for debate and revision. Any written curriculum has flaws, because what is important to 'know' is always subjective and constantly changing. Most importantly, content standards don't prescribe how to teach and learn, only what should be learned.
In my ideal teaching dream world, the written curriculum is agreed upon, discussed, debated, and revised; the taught and assessed curricula are entirely up to the communities engaged in learning to construct. Typically, that would be students, parents, and teachers. Simple, relevant. 'How we learn' and 'how we show what we have learned' should be the province of the learners, after all.
Unfortunately, bureaucracies never seem to leave anything simple. Their first victim is the assessed curriculum and their weapon-of-choice is standardized tests. It wouldn't be appropriate at this point to mention the standardized testing companies who relentlessly lobby governments to spend more tax revenue on their often tedious and arbitrary products, so I'll just focus on the fact that I don't really mind those tests.
They're not as challenging as the authentic assessment tasks my students regularly complete, and consistent test-taking practice develops important research and thinking skills. Similar quizzes also provide learners with critical formative and summative feedback on their learning throughout the year. Taking a few hours out of a school year in exchange for scientifically-collected data about the learning in my classroom is fine with me, assuming the tests are accurate and fair.
If that were the end of the intervention into children's learning, I really wouldn't mind. It turns out, however, that the companies which make tests also publish textbooks! Surprise, surprise. These text books "teach" the standards on which the tests are based. Even that isn't so bad; it's great for a classroom to be thoroughly resourced, after all, and it should provide excellent connections to the written curriculum. Until it becomes mandated. That's when this situation becomes ugly. When a school board, district bureaucracy, or central government mandates the use of particular materials, it's like when the school bully "gives" you a present and then tells you how to play with it.
It gets worse. In order to ensure that the kids "learn" everything in the books, the publishers make available a generous variety of materials. In fact, they are proud to sell 'everything you need' to "teach" those kids the standards. Including teacher scripts.
If you are a teacher who is forced to follow a script, I feel deep and bitter empathy for you. In my opinion, it can't get worse than scripted curriculum. It's a short step away from replacing teachers with videos.
There is one glaring problem with any standards as they relate to learners with special needs. Naturally, we are all individuals and not always able to meet identical standards. However, Common Core doesn't specify how most standards must be assessed, allowing teachers the freedom to scaffold and accommodate as needed. A healthy sense of equity is all we need to realize in which cases standards are inappropriate.
In conclusion, the content standards, a good idea per se, are always too easily blown out of proportion. The problem is how stakeholders react to them. On one side, reactionaries decry them for their impersonality and rigidity. On the other, standards and their associated products are championed blindly by politicians and 'reformers'. Students, parents, and teachers may feel confused, intimidated, and discouraged.
What a shame.
Use standards as a menu to help plan lessons and activities and structure inquiries to be engaging and relevant to ensure breadth of instruction. Knowing that we will 'cover everything' in the standards, we are at liberty to pursue our inquiries with vigor and enjoyment.