There's lots of interesting things here.
Firstly, there is the question of does more consistency lead to more fun? I know there are those here who have broken the singleton rule, which in doing so leads to more consistency by its nature, so I think there might be different perspectives to my question. Or is it that more decisions to make leads to more fun (which I can totally get behind and feel quite excited about)?
I'm in the other camp as I love singleton and try to avoid functional reprints. I also seem to remember a joy of cubing podcast episode (I think) that talked about cards like demonic tutor being horrible picks during drafts because they're easy and lazy picks. I know things like ponder aren't in the same boat but by themselves they don't do anything in terms of giving your deck shape and committing you to a strategy.
Secondly, you write about cantrips which I understand to mean cards with "draw a card" tacked onto it, which would apply to the blue cards you talk about but then you also included a deck with sylvan library and explore. Are you actually talking about cards that let you rearrange the top of you library? If so, would you then include cards like scroll rack and divining top?
However, I do really like your comment about decision making being fun and an important aspect of cube, which I also mentioned over in the eldrazi domain thread. If we are talking about decision making then can you expand your approach to also include (cheap) cards that allow players to have lots of choices? Eg level up, kicker, buy back to an extent?
One other thing I wanted to throw in is gnarly gnarlys modal cube which seeks to promote complex board states. I'm not sure if I've seen him on these boards but he has a thread over at mtgs (which outlines his thinking and appproach http://forums.mtgsalvation.com/showthread.php?t=418550 ) and is on cubetutor here: http://cubetutor.com/cubeblog/85
I think this cube looks awesome and might be worth a look if you haven't seen it in light of these ideas.
CML, I've recently come out of the honeymoon phase that Jason described. Any advice on how to best achieve the flattened power level that you describe? Is there any shortcut or does it just take a lot of work and iteration?
The best method I can think of is to punch my cube into CubeTutor, then sit there opening packs and yanking the "obvious first pick" out of my cube until it gets very difficult to figure out what the hell I want to pick P1P1...
Damn Jason that is such a great little slice into gameplay design. How can we affect balance so that aggressive decks feel as interesting as ones excited to play brainstorm without interesting aggro matchups (I remember playing aggro in late ravnica block in the form of both boros and rakdos decks and being amazed by how much cool decision making you got to play in decks that had been previously described as "just turning guys sideways" most of it was from the number of creature decks in the format).
I really want more colours to be able to have as much interaction with their own decision making trees as much as blue decks or decks with tutors or say funny little engines.
I also really want to live in a world (cube wise of course) where aggro cards feel like they are worth the card they are printed on. Poor lions. Does coming down 2-3 turns earlier than obstinate baloth really make you worth the same amount of the most essential resource as it?
Anyway here's a card I thought folks might think was cool x appropo
Until end of turn target creature cannot block.
Draw a card.
Destroy target non-basic land.
To fuze or not to fuze?