Nidtendofreak
Smash Hero
Between her terrible air mobility, terrible projectile, and lack of hitstun in Brawl which hinders her main spacing move, I have trouble seeing how she can wall for long at all without taking a fair amount of damage...planking really isn't even an option for her. >_>Bullet Seed isn't all that great in most matchups. It's pretty rare for it to be doing more than 20% except maybe against larger characters. I'd be more scared of Snake's f-tilt in any case.
Lately, in quite a few matchups I've had Ivysaur's role be to stay out long enough to refresh the other two. It's actually a pretty important role in matchups where I tend to switch quite a bit (Snake and Wario for example), since it can take up to two minutes to fully refresh a pokemon. So, thanks to the character design of PT as a whole, Ivysaur doesn't actually have to do all that much to be useful. Ivysaur is more of a wall-type character, so you would think she'd be pretty good at this role. Her poor air speed is one of the major reasons why she's not a good character... it's hard to keep a lot of characters out with such low air mobility.
And Bullet Seed from what I've see is a good "punish from under the platform" move when the opponent isn't at KOing %. Or I could be wrong, Ivy is the PT pokemon I give the least amount of attention.