I find it disturbing that we are so used to always online shenanigans that we don't even think about them any more.
One of the most distressing things to me is that you can buy this game, and lose like 90% of the content if you aren't online. Your items, saves, challenges, ability for unlocks... all that stuff will not be allowed if you play offline. Basically, all the things the developers added to make the game "worth it" will be lost even if you already bought them, because the always online DRM is so crucial to the experience. And forbid if steam or their servers happen to dip out while you're playing. You're booted and all your progress is lost for, again, things that are not your fault.
To me, Online DRM will always be just as a bad as the episodic piecemeal selling feature because once again, it means you're not getting all your game due to the developer's actions. It's even worse because we don't know what will happen with the game once Square Enix decides they are done with the game. Will they wave their hand and make all offline features available once they abandon the game? For some reason, given the past, I highly doubt it.