Most of the time most students attending live lectures are there to just listen. At least that was my experience when I was still studying. I found video recordings to be just as good as, or even better than, attending lectures. With recordings you can study things at your own pace, while doing exercises/experiments. You can also review the lectures later when preparing for an exam, or when you just want a refresher on some topic. And they obviously help when you have overlapping classes. You can always email/talk to the teacher if you have a question about something.
I know this is logistically ridiculous, but one time I had a teacher that was retiring, and for his last quarter of algorithms class he hired someone to record all of the lectures.
BEST CLASS EVER. I went to almost all of the lectures, but when I got home the video was usually already online - so if I missed something during the lecture, no worries, I could go back and rewatch it. IT WAS AWESOME.
Slides are terrible though - the problem is that it takes forever to make really good slides. I've seen it done before, and when it's done right it's a real piece of art, but 99% of the time slides are copied/made in haste and then the teacher just reads them off in class too quickly.
The only plus side to slides is you don't have to read the teacher's awful writing that is usually too small on a board that's too small for the giant room.
I guess I was lucky in that respect. My university taught cs in two different cities (out of the three where they had a campus), and many advanced/optional classes only had a teacher in one of the cities (with an assistant in the other). Our classrooms were equipped with video conference gear, and since lectures were already going to be through the video system for half of the class, putting recordings online was sort of an automatic bonus.
