I agree with your assessment about an attacker choosing maai. However, as long as you keep a calm, positive and connected center, the attacker almost always comes too close to you from the perspective of you being able to accurately read and subtly influence what happens next.
Sounds good Mark, this has been my experience also. I have found that this works best when one does not project any sort of "defensive stance" or "readiness to fight" per se. This often encourages the attacker to think that you are unprepared for the attack and "draws him in" or leads him a bit. Good tai sabaki and timing skills will help the Aikidoist close distance in an instant when the attack is launched, even though the attacker thinks he is relatively safe when he launches the attack.
Like you said, staying calm and centred is critical. Do you guys do any specific drills to develop this skill?