Undoing a written word or two is a monstrous pain under the double-two-finger-tap system. It might be 10 or 15 strokes that all need undoing, and pounding away on the ipad screen with a double-tap for each individual stroke takes way too long and is cumbersome.

How about: double-tap and HOLD enters an "undo scrub" mode, where you can drag left and right to move through undo history with a simple two-finger swipe gesture, instead of dozens of fingertip-bruising taps? This would be a marvelous improvement to writing flow.