"Email was not designed to be used the way we use it now. Email is not a messaging protocol. It's a todo list. Or rather, my inbox is a todo list, and email is the way things get onto it. But it is a disastrously bad todo list.
I'm open to different types of solutions to this problem, but I suspect that tweaking the inbox is not enough, and that email has to be replaced with a new protocol. This new protocol should be a todo list protocol, not a messaging protocol, although there is a degenerate case where what someone wants you to do is: read the following text."I agree that something needs to be done. If you're an information worker, you're likely suffering from email hell, and not having to triage messages for actionable items sounds awesome.
Yet I think there are two major problems to solve.
First, not all emails are todo items: They can be messages or photos from friends, bacon with offers that you legitimately subscribed to, or updates to calm the waters - hey, just letting you know I'm working on this." While you could build a system that is half messaging and half todo list, but if it doesn't support these patterns, people will use the system in addition to email, not as a replacement for it.
The second, much larger problem is this: If you build a great task management app like Asana and send out email updates when of task progress, you makes the inbox even less bearable. Thus you have to create an entirely new inbox concept - a new type of place - which users aren't yet familiar with. Getting larger companies to adopt something unfamiliar is very hard.
I'm optimistic that email can be reformatted around actionable items rather than unsolicited messages. The winner in this game will be a company that can (1) build a great new experience that is backwards compatible to the way we use email and (2) has a great plan to ease users into the new system so they can get adoption.