Highly unlikely sometimes its hard to catch sight of the l-cancel because you have to focus on them. Try putting two of them against each other and see for yourself, also he does falcon punch way to much anyway. So less is more in my eyes, he should only do it during certain conditions.
Also highly unlikely, while brawl's Ai doesn't fit well with PM engine, one thing they do right is evasion, and power shields.
That should be left optional to the cpu, forcing Ai to do a certain action in certain conditions would only let you take advantage of them. Much like in Melee where if you jump and fast fall when near C.Falcon, or Ganondorf they would only try to use up-b and miss thus becomes easy to punish.