When I enter or "At first touch" when he enters, I want to control the uke's (1) balance and (2) stability.
could the stability you describe controling also be described along the lines of binding uke's body? Not in a full on pin per se, but still creating enough of a thinning of uke's structural integrity that their power cannot recover sufficiently?
Not that I've got much skill at aiki, but when I get the sense I've initiated a techique well, I also have the feeling I can change directions and move uke around me and use them as a shield, more or less at will...as long as they keep extending through their legs and don't collapse or completely lose their balance and go the way of gravity.
What do you think?