People who have Tap-Jump enabled can easily Up Special and Up Smash Out of Shield. It's because people with Tap-Jump On automatically Jump Cancel their Shields. They also automatically Jump Cancel the pivot lag from dashes (check Luigi). People with Tap-Jump disabled should also automatically Jump Cancel their Shields and Dashes when using Up Specials and Up Smashes. How 'bout it?
How about reducing the time window for Smash attacks? For example, pressing A within 2 frames of smasing the Analog will Smash like normal, but pressing A any later will instead make a Tilt attack. This should make using Tilts easier, and ensure you only Smash when you want to.
Tilt-Sticking Fix code. Seriously, why should it make you jump?
EDIT: Oh, here's another one... Make shields and airdodges activate as soon as there's any input in the L/R shoulder buttons, instead of them needing to be pressed all the way down.