There's a few wishes the Star Rod should be capable of granting that probably haven't been acknowledged. There are entities that exist within the Star Road that are the embodiments of things people wished for, and we know in Paper Mario that the Star Spirits look at all of these wishes and decide whether the wishes are selfish or not before granting them, and they say that it is capable of granting any wish. With these statements in mind, I think it's safe to say any of the wishes in Super Mario RPG should be capable of being granted and thus should be added as abilities for the Star Rod.
There's Luigi wishing to become a great plumber, Frogfucius wishing for Cricket Jam, Mallow wishing to stop being a crybaby, Raz wishing to start a family, Belome wishing for food, Torte wishing to become a world class Baker, Raini wishing for a cute baby, Toadofsky wishing to be able to get the right melody, King/Queen Nimbus wishing for Mallow to fix Star Road and find his way home, a Toad wishing to become the greatest treasure-hunter in the world, Yoshi wishing to be faster, and Punchinello wishing to become famous.
Several of these could just be granting knowledge, but several raise statistics, create things, and probably manipulate fate. Take them as you will.