
Lady Bluehawk |

I will say right now off the bat, I way prefer Shamans to the other two, and after our own playtesting in our local group, the others agree with me (or I with them; either way). For us, Shamans have the advantages of Oracles and Witches without their disadvantages (really debilitating weaknesses for the one; a walking, "talking," fragile spell book for the other). My issue is, I'm not that personally good at game mechanics and construction, so if there's anyone out there who feels like we do, give me a holler; I haven't seen too much in the forums on this specifically. :)
LB

Lelomenia |
There’s a Class Guide for the shaman class stickied in the advice forum if that’s what you are looking for.
Not really a general way to convert witch/oracle to shaman (beyond “nature patron/mystery => nature spirit”, etc); if there’s a specific build to be converted, could help with that.
For the classes, witch and oracle certainly have plenty of roles and niches they are great at, but yes, shaman has a lot of benefits of both of those classes while avoiding issues with them that are common complaints (while lacking other advantages of those classes and adding some new issues, of course).