Re: committed attack/sensitive ukemi paradox
You have much more experience at this than I, but I'll try to explain what I mean.
To me, "committed attack" means uke WILL strike or land the grab at full force if nage doesn't get out of the way or otherwise disrupt the attack on the way in. Uke executes the attack from a structurally sound, balanced position, but that position is not fixed in space (i.e., "rooted"). Good examples are the attacks you get from Ledyard-sensei or Lasky-sensei. You have no doubt that they'll land it if you don't move, but they're never standing still while they do it.
Knowing that no matter how well he executes it, uke's attack may not succeed, uke is prepared to conduct a fluid, continuing engagement. In kihon waza, this means reacting to nage's well-applied kuzushi, and "riding the surface" of nage's technique while simultaneously attempting to recover their balance and looking for openings to launch the next attack. If the situation becomes untenable for uke, (no viable openings present themselves and uke cannot regain his balance), he smoothly transitions his movement into ukemi, which takes advantage of the available "escape ramps." inherent in nage's response pattern.
Does this make sense?