As to the Epicure, I am not exactly a fan. I have a minor nitpick with the card itself - it deals damage to each opponent, to make it more relevant for multiplayer, but makes only one token. Like void said, it is a red's play on draining and I like when those effects are scaleable, like in
extort.
The bigger issue I have is with the blood tokens itself. They are fine in the vampire context - sacrifice represents consuming the blood, and the
rummaging is the stimulation of senses/rush of vitality a bloodsucker experiences. Since they are called blood tokens, one might do flavourful things around them, like
Arterial Alchemy,
Bloodvial Purveyor or something like:
Vampire Flea Marketeer
Creature - Vampire Citizen (C)
Sacrifice a token: You gain 1 life. If the sacrificed token was Blood or Human, you gain 3 life instead.
2/1
However, get rid of the vampire context and let the blood be a standalone token. For instance a plane, where blood-magic is widespread around all colors, that has little to no vampires, since they were considered anathema by every other inhabitant of the plane. Or a plane with an alchemy focus, in which usage of blood might be uncommon, but not rare occurance. In both cases trying to not use Blood tokens, when they exist, would be understandably a strange decision, if not an excersise in reinventing the wheel. But at the same time the rummaging does not invoke "blood" by any metric, once you alienate blood from the vampire flavour.
The other pre-defined artifact tokens are more cohesive between their flavour and effect. Thanks to this they are much easier to use as a card type for non-token artifact. For instance, I can make such cycle:
Gemstone Golem
Artifact Creature - Golem Treasure (U)
, Sacrifice this artifact: Add one mana of any color.
1/1
Cryptic Golem
Artifact Creature - Golem Clue (U)
, Sacrifice this artifact: Draw a card.
1/1
Meat Golem
Artifact Creature - Golem Food (U)
,
, Sacrifice this artifact: You gain 3 life.
1/1
Blood Golem
Artifact Creature - Golem Blood (U)
,
, Discard a card, Sacrifice this artifact: Draw a card.
1/1
and I think most would agree that the last one is the only one that doesn't make sense in terms of flavour without some flavour text gymnastics.
I am not sure what effect I would prefer instead - the most obvious one, draining (
, Sacrifice this artifact: Target opponent loses 1 life and you gain 1 life) is actually not that better - we are still bound by the vampire flavour, only now it is more explicit. Maybe straight up lifegain, to represent transfusion? It would tread to much on the grounds Food covered. Producing mana that can be spent only on spells/abilities targeting opponent's permanents? This would tie into hexing aspect that usually goes hand-in-hand with blood magic, but it still contrived.
To be honest, I would prefer them to not exist actually, since Blood as an artifact type with a distinct, mechanical aspect, is - in my opinion - just not representable in Magic.
As for the Lord of Shatterskull Pass, while maybe not most exactly thrilling design - you have to invest a lot for the power you are actually interested, unlike more gradual increase like
Echo Mage or
Enclave Cryptologist - it still nice tool for control shells looking for a long game and a limited bomb.
The whole level up mechanic is a throughly limited design - it gives you a way to fuel your excess mana, while at the same time - due to sorcery speed - it asks to be in environment where instant speed removal is not widespread.
I personally would not bother to design singular cards with level up, but I would certainly considered the mechanic in custom set design.