I'm not going to name the person, but I recently attended what was meant to be a class on ethical relativism in SL. I want to make two sets of points about it, which is why I'm mentioning the topic.
Firstly, I'm pretty sure it would have been a disastrous class in ANY situation, it was much more like a thesis defence than a class, and some of the examples chosen were stupid or just wrong. The most obvious of these, to illustrate that (in the defendant's opinion) the ethical relativist stance of "what the majority believe becomes true" he chose the example of "If they believe the moon is made of green cheese does that make it true?" Um, what?! They can believe what they like, but it won't change physical reality mate. However, believing, say, women are more emotionally stable than men and thus should be given more responsibility is a cultural stance, and one that could be regarded as part of their ethics (It's a steal from a sci-fi story btw, but can't remember which one). There you can ask if it becomes "true" or not - although it becomes believed and defended as truth, just like women are stupid and can't be trusted to vote was a "truth" for many centuries.
It was also a disaster from an SL teaching situation. Where was the interactivity, the exploration, the integration of the special things SL lets you do? This was an oddly structured pseudo-interactive presentation of a thesis, followed by an incredibly poorly managed discussion. A number of potentially valid criticisms of his stance were ignored - too hard to cope with perhaps? A number of weaker ones were picked up, but increasingly inconclusively dismissed. With a gratitude it is hard NOT to liken to that of a drowning man, any crumbs that were thrown his way were clung to, until they became nibbled away by the sharks.
I've seen, and moderated, toweringly controversial debates and discussions in SL and they can be brilliant. They can go out of control too mind, and they have. I have still yet to see a good lecture in SL. Classes in which the teacher speaks more than everyone else, yes, but pure lecturing? No. The combination of a lecture that didn't make sense AND a discussion the speaker lost control of within two minutes - ouch.
Writing this has made me realise though, why, I think, I've never seen a good lecture in SL. It's a speed thing. Unless, like Cory, you prepare it all in advance and do a huge info dump people have time to read and think about each statement and think more deeply than they would IRL, where they'd probably be scribbling things down and trying to take notes. This leaves the nativesstudents restless in some senses, because they're used to taking notes and not thinking, now they don't have to take notes and can suddenly think in class.
A led class is still different to a lecture, and although I don't use it much, I do use one regularly in SL. Why and what? Well it's the first class of my scripting course. It's heavy on syntax and structure, laying the foundations for the rest of the learning. I've tried without, and it's much, much worse, despite the fact I think this is the weakest of the classes in the course by some margin. The reason it's different to a lecture? It's not just it's to a smaller group - it remains more interactive. I ask questions where the answers matter. The students are encouraged to interupt and ask questions, and do so with abandon. It wouldn't work as a lecture, because the class tugs and drifts all over the place, whilst making sure it covers the ground - it is an interactive learning experience in which the learner has some control over speed and direction of learning rather than receiving an info-dump. These differences between the what is essentially the same class have been highlighted for me this week - I've taught it 4 times and all have been very different - and have reinforced my decision to keep it as one of the clases: the learners ask different things and struggle to learn different things, hence the differences in pacing etc. which makes me suspect it's not something that could easily be done as a handout.