I love the Brawl Falco playstyle. Camp and safe things + punishes or baits is the things I most enjoy : )
Well Rosalina is extremely safe in a lot of cases. She has her little Luma helper, after all, who can not only attack for her, but act as a damage sponge/"star" shield. Because of Luma, she can definitely camp too (albeit a totally different kind of camping). Just send Luma out with Luma Shot (which is a very strong projectile move), and let him at your opponent.
Rosalina is great for punishing and baiting too. Luma can be used to bait people, and you can punish them for giving him too much attention. She can also force projectile users to approach her, since her down special denies pretty much every projectile in the game (and then some), and it's really easy to use too. Her dash attack also comes out very fast and has excellent reach, which is great for punishing. Having Luma nearby when you do it also makes the range even more ridiculous, and you can dash right through most projectiles using Luma as your shield, and punish with Rosalina's Dash Attack.
Rosalina's Up Tilt and Up Air are also really good for punishing people trying to attack from above, and Luma again makes the range even more ridiculous. Not only that, but they are also KO moves. Up Smash is also great for this, and can punish people approaching from the ground too.
Down Smash is also really good for punishing rolls (especially useful since rolls are so good in this game. Rosalina herself has one of the best rolls too). Especially if Luma is present, since you can then cover both sides at the same time.
And since I know Falco's D-Air spike has been one of his signature traits in past games (I know it helped influence my choice to main him in Melee), you might be happy to know Rosalina has a D-Air that can spike:
It's weaker than Falco's spike was, and it's kinda difficult to land on the 3DS, but it's definitely very useful and getting it down would be awesome. It's also not very risky, because unlike Falco who couldn't recover very well compared to others, Rosalina's ability to recover is one of the best, if not the best, in the game. She can recover from the magnifying glass with ease most of the time.