It should be fine, you can fast fall and DI after the up B, and very well too. Falcons can Fast fall Knee, but platforms can make you avoid getting punished, cause you can fast fall through one, and while he is spinning out he can not. But for Dorf, just DI away, they will often just go straight down and try to Fair or something, but you should be fine vs Dorf. Just go away and fast fall.
Vs Falcon fast fall on the spot through a platform, you will be safe. Often he will try to drop through platform and hit you again, even though you can always avoid it, thats a chance to up-B out fo shield again, and piss him off even more.
Getting agry and playing melee do not go well together. It helps so much that Samus is an anoying Character to fight against. =)