At 1:12 after the ethereal vs blade trap the door looks like it was opened with a spell to me.
Ummm...I didn't see a spell getting cast there. Doesn't look like that door was locked.
But it doesn't matter. I don't believe that Open Lock spells are out of the game. That would be stupid. Plus, we know for a fact that one of the stones gives you a spell to open locks, and it would be REALLY stupid if that was the only way to access a magical method of opening locks.
In short, the OP is simply a rumor.
Yes, I know, absolutely shocking...