Seems like to many steps to me.
As I remember it, GTD does suggest having multiple to do lists based on where you would do each type of task. I think having your emails to do list in your email makes sense. If responding to the email requires you to do a lot away from the computer, than it makes sense to put it on your other to do list.
Also, I'm not sure I'd like to have email subjects, etc... on my to do list. I don't usually keep my list that granular since a lot of the tasks I need to do are pretty amorphous until I actually start on them and figure things out. Maybe its not the best way to do it though....
Instead, I flag emails I want to respond to/come back to soon. Also, any emails either a) directly to me (i.e. not to a mailing list I'm on) or b) from my manager(s) gets automatically flagged. Once a day I go through and clean up all my flagged emails.
his method: click "unread" P times
yours: click "archive" A-P times
A-P >> P
His method is less work.
In triage method A (his method), you first page through all your unread mail (1 click/keystroke to open the first, then A - 1 clicks/keystrokes to advance to the next conversation without returning to the inbox, and 1 final click/keystroke to go back to the inbox.) Then, once you've seen them, you select the mail you want (P clicks requiring dexterity, or A+P keystrokes; it's a compromise) and mark them as read (1 keystroke.) M_a = O(A + P) = O(A). (Because, as you said, A >> P.)
In triage method B (the "naive" method), you page through all your unread mail, and at each step, you either advance to the next conversation, or archive the current conversation and advance to the next conversation. (1 click/keystroke either way.) M_b = O(A).