I'm all for competition but there is nothing more unappealing than the way the founder is acting about his product. After reading the security article I did a look around as well and the thing is still wide open. The security on it is like a piece of swiss cheese. It's sad that he didn't just acknowledge the issues and let everyone know a security update would be on it's way or hell even hire or work with the guy who pointed out the flaws and clean everything up.
I'd be open to a new open service, if and only if it really went above and beyond our current expectations of email providers today. I think gmail(what I currently use) is great and I'm satisfied with it but it doesn't mean that I wouldn't switch if something could out-do it in certain arenas. I think the obvious factors of security,privacy and UI/UX would be the things that would really have to shine for me to open my wallet. I'm not sure but I think that the market has some pretty decent offerings and people might not be on the lookout for a new email service but to make an example; I wasn't looking for a new text editor when I came across Sublime. Sometimes thing are so great that they are just worth trying. It would be a large undertaking on your part but who knows how it could turn out? Good luck.