I think it's a great idea to be straightforward. For one, you make sure you are communicating what you are looking for in terms of a reply. You are also being efficient time-wise. I don't know about therapists, but I know I mostly just look for the point in any correspondence and address that. I also work with people who can't handle more than two questions or concepts (nothing to do with intelligence, they are just very busy), so I have learned to cut to the chase.

I don't know how you resolve this, but being direct is worth trying out.

You've seemed to be concerned about coming across as needy, but there isn't much a decent therapist is going to miss under a pile of words that try to show otherwise. My therapist knows what I'm driving at, so I don't even bother trying to cover. I just come out and say or ask. If I am being needy, she already knows that, so I don't want to have my denial on display on top of it. Besides, there are worse things about me, I think, than wanting a reply to an email.