If you are moving toward all writing in class, here are some ideas to consider to make in-class writing work.
The primary goal of using in-class writing is to allow students to slow down their thinking, demonstrate what they have learned, and provide evidence of "understanding."
In-class writing works best when the goal is to develop aspects of good writing over writing an entire paper.
Spend time on the rewriting.
Be ok letting go of some things about your teaching practice. This may mean mini-lectures, abbreviated discussion, and compression of background information.