Peach does have power, in some games like Mario Party 3, Peach was said to have the power of Love. I don't know if this means anything, but in games like Paper Mario, they used Peach for that demon cuz she HAD a pure heart, and also on some games she had massive healing abilities (heck, even on SSB)
I really feel like Nintendo should give Peach more credit, since I know she can do a lot more. Heck, maybe they can make a M&L game, and have more party members, like Peach and Toad. (Though it's called M&L for a reason, they added Baby Mario and Baby Luigi lol :P)