I've marked here, with an asterisk, those cards that I consider conservatively and uncontroversially "hyper-efficient" in terms of mana cost, and they add up to over 60% of the list. I didn't even count cards like Young Pyromancer, Toxic Deluge, or Scavenging Ooze that I also personally consider very much under the curve.
There are some cards that are not hyper-efficient, but that still show up due to their unique effects in the context of the Vintage metagame. Laboratory Maniac, Notion Thief, and Talrand are good examples. These, however, are a tiny minority, and it should be noted that over 80% of the playables in this list cost 3 mana or less.
There are some cards that are not hyper-efficient, but that still show up due to their unique effects in the context of the Vintage metagame. Laboratory Maniac, Notion Thief, and Talrand are good examples. These, however, are a tiny minority, and it should be noted that over 80% of the playables in this list cost 3 mana or less.
I don't think that each card you mention is uncontroversially hyper-efficient. Dryad Militant, for instance, is not an automatic 4-of in every aggressive green or white deck in Standard. For a 1-mana creature, a 2/1 with upside is par for the course for modern constructed Magic. That its upside hoses the graveyard would seem to support Stephen's point, which is that it's most important to look at the effect that a card has on Vintage strategies and tactics rather than a simple calculus of "how much do I get for my mana." Memory's Journey is an even better example; it's the graveyard-ness that gives that card its Vintage playability. One mana is about the right cost for such an effect. The card saw very little play in Standard and zero play in Modern (unless I'm missing some tier 2 combo strategies that use it) despite it's low mana cost.
On the other hand, hyper-efficient cards that don't interact with Vintage strategies and tactics don't matter very much. Hyper-efficient life gain, for instance, probably wouldn't see much play unless it got really out of hand. A card like "G, sorcery, gain 15 life" would basically break Standard, since it would blank any burn strategy and most aggro strategies. I can't imagine it seeing much Vintage play (although I could be dead wrong about this, so I'm open to this being a bad example); at best, perhaps it would enable a deck based around paying even more life than Vintage decks already want to pay. Same thing for, say, Giant Growth effects; maybe a really efficient one would make Infect a top strategy? But failing that, Vintage wouldn't care at all.
