I personally really like the idea of being able to summon the variety of spirits man, plant, task, etc with the differences between traditions determining apperance and basic affinities. So I'm slowly working away on opening up more summoning options and this is where I am currently. I'd appreciate feedback on whether people think it would be a balanced house rule or not?
Metamagic: ? (possibly Advanced Spirit Summoning).
With advanced spirit summoning the mage has learnt to expand their options when summoning spirits beyond what is normal for a follower of their tradition. For each rank of initiation that a mage posses they can choose to summon an additional basic spirit type (Air, Earth, Fire, Water, Beasts, Plants, Man, Guidance, Guardian or Task) OR to add an additional role not normally found in a spirit type they can already summon for their tradition. More unusual spirit types e.g. blood, toxic, shadow, ally, great form can not be selected using this metamagic.
So for example a follower of the Shinto tradition can summon Summon Air (Combat), Water (Detection), Plant (Health), Beasts (Illusion) and Man (Manipulation). If they take this metamagic they can choose to learn a new spirit type to summon (at which time they must assign a role) e.g. Fire (Combat) OR to expand the roles of a spirit type they already know e.g. Man (Manipulation, Health).
I think its reasonably balanced as you'd need half a dozen initiations to summon all the spirit types and more initiations than most PC's will ever see to get all the roles on all the spirits. However I would appreciate feedback as an alternative I was considering was splitting it into two metamagics one for spirit types (Earth, Air, FIre, Water, Beast, Plant and Man) and one for spirit roles (Guardian, Guidance and Task). Thoughts?