Have you seen Facilethings.com? I wish doit.im would implement GTD flow the same or more similar way. They set great example of GTD consistency. I mean:

1. Separate Checklist box.
Actions and Routines with checklists. You could also import checkpoints from previously created checklists whenever necessary.

2. GTD flow: Collect -> Process -> Review states. I love the Review especially. It's a 100% step by step implementation of David Allen's way.

2. No "Today" and "Tomorrow" boxes - in Doit.im they somehow disturb GTD flow. Today should be merged with Scheduled and renamed simply to Calendar. There are already Next Week, Next Month and Later Tabs. Why not add Tomorrow and Today?

Star should go for Focus, but when I star something I don't want to necessary set date and move it to my calendar. If it was something I'm obliged to do on a given day I would place it in my calendar on the first place. It may take more than one session to complete some actions and I could plan to complete it in more than one day, not necessarily on following days. I wish I could Star and UnStar freely without being obliged to complete the task on the given day or manually deleting date and moving it back to the Next Actions list every time. Actually I use priority and Saved search to deal with that issue. Star is, in my opinion, misleading.

3. Full implementation of Perspectives

4. Way it handles Projects, although I would explicitly add Action states: In Progress (or Active) and Waiting (or Planed). They do function but implicitly. There's actually no way to have two actions from any given Project active on the same time - it would be beneficial in some cases. In Doit we have nothing alike.

5. Connecting Evernote notepads to Projects. Notepads act as the Reference Material filing system. In Doit we can only attach Evernote notes to actions. What about Reference Material? They belong to Projects not Actions!

6. Tickler File and Start dates. Actions go to Tickler File while having set a Start Date. When the day comes they will be moved to Next Actions list or to Calendar. Alen states, that they should be moved to Inbox again to explicitly decide what to do about them.
In Doit.im there is no real Start Dates and no real Tickler. Scheduled are regular Calendar items and will eventually land in Today box. Instead they should form distinct and separate category and be moved to Inbox again, when the due time comes, because they are something different than calendar items.

What I don't like in Facilethings.com is the price, graphical interface and some minor flaws.
Do you plan to make Doit.im more GTD driven in some not very distant future?