But to answer your question, yes, I can remove the avatars completely if they're switched off. To address your other concern, I don't see how the spacing could get any tighter vertically. If a forum has announcements, they're going to push down the rest of the content. That's just the way it is. Compressing everything so it all runs together results in poor readability and difficulty in navigating page contents. I don't consider the whitespace a waste at all.
If whitespace were a waste, all web sites, magazines, and newspapers would look like a page from a dictionary.
Closing this topic down now since most new posts will probably be more appropriately placed within the comments section.