The 2♥ bid makes it a lot harder to find slam here since, at the point where opener bids 3♠, responder does not have much extra. I think that if the auction were to begin 2♣-2♦-3♦-3♥-3♠, and 2♦ is waiting, then 3NT is a terrible bid. I think 2♣-2♦-3♦ should show extra values if you are playing that a 0-count can respond 2♦.