Since one of our goals is to facilitate the writing process, keep the emphasis on students' ideas rather than your own. It's best to remain mostly objective on thematic issues discussed in class. If students pick up on your views, they may attempt to only write what they think you want to hear. This keeps them from thinking critically and forming their own views. Also, if you share too many opinions, students may refute these in class. This puts you in a position of having to defend your views.