Live Chats in Classes

A few possible teachers have told me that time is a big issue for them, especially having to lock in exact times for doing live chats/lectures.

Should the chats be optional for teachers & students? Should some classes be forum-only?

I was thinking that it might be much easier to have some classes which have all the lecture material online and then the teacher will set aside certain times they will be in chat to answer questions or have discussions. Or they could be completely forum-based, with no chat times.

The downside to this would be that the classes may be generally less appealing, since it is much more engaging to learn things in a live chat than it is to read a post on the forums (it wouldn't be much different than reading a tutorial). But it may be possible if there are specific class threads for questions and problems.

Im assuming that I would want to do live chat frequently but with the time differences I think trying to do two short sessions in one day possibly in the morning and one in the evening students could have two options that day to join the live chat.

Above is an example of a run-on sentence.

Live chat classes are good but need to be structured very well. I think a more personal form of teaching to accompany the forum classes is necessary, if professors can't set up planned live classes then they should perhaps devote what unplanned free time they have to just further PM tutoring or spontaneous mini chat lessons if/when students are available.