I was really intrigued by the first screenshot, I thought "wow, looks promising". The next screenshots for the settings threw that promise out the window. That does not minimal at all.

I would like to see a minimalist email client with a nice simple UI but maybe text-based config? A crossover between TextMate and pine.

Edit: thanks to the comment below, I had to read the post twice to get that it was not a new app and just a reconfig of Mail.app duh...