I get a lot of requests to speak at conference now. More than I can possibly accept! This is a marvelous problem to have, and I'm delighted that there are so many relevant conferences and that a lot of them want me to be there. Sometimes if I decline a conference, it's just because I am doing something else in that time frame - I try not to do two conferences in the same month, for example - or the travel would be too far. But there are other reasons, so I wrote a little list of requirements and preferences. If you're running a conference, please check this list before you ask me to speak. If you're a speaker, consider putting your own list together. We can make conferences better!
And yes, I am working on a much longer list of what makes conferences great. It's over 4 densely packed pages right now and likely only to get longer. I will advise any conference-runner who asks me and genuinely wants to improve. Want my opinion of your badge, website, code of conduct, or the like? I'm happy to help.