Yah from what I've read just a decent chestpiece at endgame has about +20~25 of your main stat and then 2-3 other stats that are slightly lower on it..so +30 stat points is seriously small. the materia is the part where people will get most of their non-main stat points.

Really though having mind on a smn alongside the int is going to be kind of a gamble...either it won't work because stats are stretched too thin or it'll work really well and be a nice niche for people who enjoy supporting, hoping for the latter but if the former happens then I'm not sure what class I'd want to roll anyways so I'm putting all my eggs into this basket. *crosses fingers*