Does anyone else find it slightly disappointing that the spirit summoner archetype doesn't gain the benefit of 'spirit animal' or the 'manifestation' ability for the shaman spirit? I honestly would have LOVED to replace the Twin Eidolon ability for the final spirit manifestation, and the 'spirit animal' ability would have been perfect for the eidolon as well.
Well he doesn't have a familiar so he couldn't apply it to anything. Also most of the spirit animal abilities can already be obtained through evolutions. I do understand what you were hinting at it's just the eidolon can already do most of it already which usually costs more.