Logic should be beneficial to one of the three skillgroups. As is, Shamans are naturally inclined towards spirits (from having a higher bound cap, and even just in flavor). Charisma is usually the "spiritual tradition" stat. I'd like them to make Logic the alchemy/formulae/enchanting one, as it would fit with the flavor well, then I dunno. Have Intuition be best fitted to spellcasting and ritual spellcasting. It's actually already what you use to decrease the time needed to learn new spells.
Logic is currently used for Arcana, or at least that's how it's listed, but that doesn't seem to actually be the case. Making foci formulae uses MAG, and I don't think 5th has rules for making spells or anything with spirit formulae.