I've been wondering about this for some times. TCG exclusives tends to be expensive and sometimes, they have some broken effects. IIRC Gravekeeper SD was released because not all of Dragunity has been released in TCG yet. So, SD Marik is just a SD to wait SD19 a.k.a Dragunity.
But now, they made Six Sam SD, together with some new rarities. Six Sam itself has been always a strong deck and now, they gonna add some TCG exclusives which usually, broken and supports the deck much better. GK has been powered up a lot and now, Six Sam is gonna have the same power ups. Maybe Konami is just trying to milk money from the Yugioh players to spend their money on TCG exclusives in order to make their deck still competitive in Zexal era. I don't know. But the fact that they made a new rarity and independently made their own SD, makes me think there's a possibility they are really trying to separate themselves from OCG.
EDIT : I just got a rumor that priority rule will be deleted in TCG. So, maybe it's not entirely separating. And maybe, if TCG really did something like this. There's a possibility that OCG won't release any more Structure Decks.