I work for a company that heavily uses Linux and work in a position where I do all my work exclusively remote via web share/phone call. So we need a web sharing application that is stable on linux & windows. We've had good success with Elluminate (now owned by Blackboard). It's re-paint algorithm seems to be bearable.

Great suggestion about #2. I know a number of my colleagues that don't get that. And screenshare a 1080p display and don't even use a fullscreen presentation. So the text is completely unreadable on small screens.