Differentiation is the name of the game if you want to replace homework with in-class work. Or at least if you want to push the balance further in-class.

After notes or an investigation (math) I assign maybe 25 problems with the knowledge that only the top 4% will complete them.

Some students will move through only six of them and it's my job to make sure they are giving huge, concentrated effort on those six. The top 4% move through all the problems and it's also in my job description to have thought up some interesting extension problems -- one or two -- to keep them engaged until the end of class.

This is all an effort to make the hour-long class work for everyone. There is only one conclusion to draw from all this: eliminating homework makes the teacher's job harder, not easier.