I feel like, based on this premise (which I don't disagree with!) we should do some analysis of these formats to determine where they are similar, and where they are dissimilar from other formats. Cantrip density is certainly one axis to look at, but things like creature size to mana cost, removal efficiency, creature butt size to damage output ratios and other shenanigans like that would help. Maybe I will do this at some point. Maybe.
This is worth a read in that respect:
http://puremtgo.com/articles/ars-arcanum-rgd-draft-and-rtr-mechanics
It talks a lot about how you plan your draft through the guilds and the three different booster packs. This planning an anticipation was certainly one of the enticing things about the format. It's pretty impractical for cube though.
What is very interesting, is that the article talks about the speed of the format. It states three reasons:
* Karoos take up a turn in the early game (and are prevailant)
* Decks are three or more colours and so you spend the early game fixing your mana (signets etc)
* Lots of creatures with low power and high toughness that gum up the ground
Other observations from the article
* Games come down to topdecking
* Auras become better because of this
* You have lots of mana available (karoos, signets, slow environment) so mana sinks and expensive creatures become better
Are these the reasons why a lot of us think that rav block is fun? If it is and we tried to apply it to cube, and not just cantrips are cool, what are the implications?
There's a big school of thought that doesn't like the signets. How many mana rocks would you need to match the frequency they showed up in RAV boosters? I would imagine quite a lot.
If you applied these lessons, what would it mean for traditional aggro? An interesting follow up article, if you have time to skim read it, is his review of Return to Ravnica block. It talks about how the fast guilds have a negative effect on the rest of the guilds in the block.
In relation to the multicoloured aspect of the block, there's definately an appeal here, what with all the powerful effects they bring. The problem which we all recognise, is that it can lead to too many dead cards during the draft, especially when you have a smallish number of players during the draft.
By far, I don't have all the answers, just more questions.