I doubt they will but I think they should.

Reason being, is that it's an MMO standard that inventory space is upped when there's a new expansion. Like WoW has it's bags that tailors make, and FFXI apparently had quests.

I have no issues with the store apart from retainers. This is a gameplay feature that really should be covered by the subscription fee. Everything else on the store is novelty and perfectly fine, but storage space shouldn't have to be paid for. It'd be more okay if there was plenty for free, but there isn't.