We are planning to add iOS version in the nearest future.
Mail to inbox is already available.
You can send email to inbox@mail.taskscale.net from the email address you are registered with and it will get to Inbox.
In GTDNext we had the option to create an email address to which you could send tasks from any email address, not just the one you are registered with. For example, I am registered with a personal address but I would forward work tasks from my work address to this address I could create. Will this be possible at some point in Taskscale?
If I may, one more to perhaps add to the back log is the ability to force Next Actions. In GTD Next you could force a task to be a next action, even when it wasn’t the very next action on the list.