Seems more like a series of feats than a monk fix to me. I do kind of like the concept though. Mechanically, it's a little like the Rend ability: extra punishment to a foe when you land more than one hit.

Could also do Wing Chun punch: Monk attacks at his highest BAB. If he hits, he gains a free attack at his highest BAB -2. If he hits again, he gains another free attack at an additional -2, and so on until he misses. Then he starts his iterative attacks (don't know if they should also grant free attacks; probably wouldn't matter, they'd stop pretty quick).