Great video with a lot of great points on both sides! I feel the same way about the same style of teaching may not work for every subject straight across the board.
I think that "jack of all trades, master of none" effect can definitely be a common side effect of trying to use an all-in-one curriculum for language arts.
We use a whole in one language arts curriculum and we love it but we do our own spelling as well as the spelling that comes with the curriculum depending upon the spelling pages in the curriculum and the kid!!! We love gather round but don’t do all the pages depending upon the kid!!! I love not having to do as much planning especially as I’m in medical school and still homeschooling our kids!!! We use different phonics curriculums as my kids are dyslexic!!! We do extra writing assignments for writing as well as our curriculum and some of the assignments are for other subjects!!!