Sparrow is so close to this. All it's lacking is the all-attachments view and the prioritizing, but you can hack the prioritizing easily enough with Gmail labels. Even then, I don't think that's enough, though. I think e-mail nowadays needs to be more of a TODO manager and less about messaging.
Agreed, 100%. I saw the screenshot and thought, "Oh, it's Sparrow with some red colors and a new little organization feature. Neat."
Sparrow is literally this exact client design, minus the cute "Actionsteps" or whatever. They could easily add some more color coding to Sparrow and it would fill this need pretty easily (well, that and fix some annoyances, which as is usually the case, is the larger usability problem—simply not being annoying).
More importantly, you're right: e-mail is no longer just communication. Our e-mail clients are how we organize incoming tasks and work. This is why GTD and the like focus so strongly on e-mail, because it's become our primary means of incoming information. Organizing that is the problem, and it does need a solution.
This is so close to Sparrow because it completely rips-off the Sparrow's design.
Take a look at the compose new mail window, it's the same except the send button is red (and I think the bcc line has moved up). The toolbar icons and order of the icons are identical to Sparrow.
All sorts of other little things that could be different too are not, like the select state of the current email.
It would be ok if he, at least, mentioned that it was based on Sparrow.
There's one or two original things in the design, for example, he put his url in the left corner though.
