Actually, in the training centre I once worked at, I often just binned the textbook activities and made my own activities of superior quality, based upon the original contents of the textbook.

However, you have got to bare in mind that some Chinese students lack the ability to think for themselves and will complain if you deviate and don't use the book that the shitty TC has forced them or their parents to splash out big bucks on. One book I heard, cost 190 kuai a pop, compared to 9.9 kuai for a book commonly used at the local public high school.

One teacher used to never use the textbook at all, making it clear that the textbook should ideally be used only for preparation or reference.
He is a far more qualified and actually probably a better teacher than me, yet he'd always get complaints for not using the book. Mind you, that's the nature of TCs, kids and absolute mongs of customers are given the responsibility of judging teachers rather than real educational experts, so emphasis is placed upon dancing monkey skills rather than true education.

Then again, I've actually had a similar problem with a job at the university, a shitty textbook and one particularly bad class of 'adult learners', students who failed the Gaokao and do a vocational non-degree course. If you deviate from the textbook, they all seem confused as hell, so you have to make up your materials, because the materials given are of a level that is far too advanced for them.

However to their credit, the university was very honest with me about this, admitted that the textbook was shit, not only allowed flexibility but encouraged it. They also gave me accurate information about those students, allowing me to understand how these kids had somehow got into a university! My other classes were real university student filled classes, thankfully.