Copycat startup accelerators are stupid

If you pick a market segment of founders, focus on it, and stick with it, you're going to get a much better class of founders. Your accelerator will be more valuable to them, and they will get more out of the other founders they meet through the program. You'll also have a brand that will be attractive to follow-on investors who are interested in the space, and you'll be able to get the enthusiastic participation of high-quality mentors.