I think with new features suggested you need to create a new subscription with new pricing. For example:
- It would be useful to add a link (mail or web link) in the title of task. "Send project to Mr. Smith" with inside the email link. It would be useful to have a link in notes too.
- Add Contacts feature, sync with mobile phones contacts. Then I can combine a task (and single subtasks) with one or more contacts (like Tags). Then I can sort tasks by Contacts, or group by it.
- Less important but interesting and fun: for each task (and subtasks) insert a location (like remember the milk) and show all locations on a google map with all the flags for each tasks (a very simple approach to geo-marketing).
With these features (and with sharing common database for folders, tags, goals, contexts, files) the annual price would be very interesting for you and we could have a precious service.