Nostalgic Dreams: I really wanted this to work, but found it to be under-desired; often a 14th-15th pick type of card. The problem is that the average case scenario is not up to snuff. Yes, the sweet interactions exist but there are not many of them ...and when you don't get the sweet interactions, it is worse than Regrowth 90%+ of the time. You have to put in work to make it an above average card.
Nostalgic Dreams is a completely different card than Regrowth. I can see it being 14-15th pick in most groups, but for slow cubes it's one of those cards that plays way better than it reads. When you turn 2-3 lands into cherry-picked gas, it's a game winner, and cheap enough that the returned cards can be played on the same turn. Also, it strikes me as the perfect card for dedicated graveyard decks. Return that Necromancy that got milled for the Sundering Titan you drew.