It sounds a lot like you are describing Asana. It is designed with teams in mind but the personal workspace can easily be used for personal stuff and allows del

It sounds a lot like you are describing Asana. It is designed with teams in mind but the personal workspace can easily be used for personal stuff and allows delegating including to guest users. It has an inbound mail feature that works well. The only thing I don't know about from your list is the mailbox style app. Their app doesn't seem to use many swipe features. I have messed wit trello. I live the way it looks but Asana fits how I think better. I think that is a big part of why people get wrapped up in the tools they like - it works with their way of thinking. If you process things differently, you'll have different feelings about it.