I'm biased, because I came up through support before I went into engineering.

But to me, the question has always been "Do I think I'm omniscient as an engineer? Do I think I can imagine every way the customer is going to try and use this product? Every way it can interact with other systems? Every quirk of a specific customer environment/dataset/etc.?"

Well, if not, then good news! The support org should be capturing, categorizing, documenting, and forwarding all those cases to me.

And each case is an opportunity to make the product better!