Old news, and not that useful, anyway. If he throws in F-Air, you get hit by the second and third hits. If he mixes up his timing at all, you roll toward him and get punished for being dumb. You still have to worry about people jumping off the ledge later, and if you're that close to the ledge (in order to Shield SDI), then N-Air molests you.
If this option select you mentioned works, you can still get nailed by a move during your roll's start-up.
It's nice to have the option, but you're crazy if you think that double U-Air alone is what makes Meta Knight's planking gamebreaking.