Can't say what features in the future, but how they have to tackle inventory expansion and housing is already something that raises some concerns.
As for the extra inventory slots, as the game progresses they keep adding items, now quantity of items is less of a problem because of the increased cap, but if the pool of items keeps increasing while our inventory doesn't we run in some problems. Consider that wow releases bags with 2-4 extra slots with each new expansion to partly combat the increased item pool.
I would say that FF14 item pool is not as big as wow since they tend to add too many junk items but still an inventory expansion every now and then doesn't hurt, mind you I'm not saying we didn't get anything sop far, but we could've got more.
I was expecting them to release craftable saddles to increase our inventory as to make it more involve, but eh I suppose it wasn't meant to be