Going over the top with more expensive spells.
Sure--by going over the top, I mean that in my draft, few cards looked as if they could generate an overwhelming advantage, which is generally where midrange and control want to be. This is to say that a lot of my choices felt as if they were between different flavors of incremental advantage, which is great to have on, say, 80-90% of cards, but can mean that once you're solidly behind or ahead it's hard for that to change. Take
Oblivion Ring, for example. This card is great at locking up a lead or in stemming the flow of blood when you're getting stomped, but it's rarely going to swing a game in your favor (in this cube, according to my assessment, usual caveats, etc.) because most cards feel relatively equivalent once they're on the board. Part of this is the fact that a lot of your higher-MV cards aren't nearly as good as the lower-MV ones. Sure, they're better than they look, but
Solemn Recruit is, 9 times out of 10, better than a
Striped Riverwinder or a
Bone Miser by the time you play them, and that's without looking at the difference in mana efficiency.*
You also just don't have many ways of getting an X-for-1 where X>2. You only have five wraths in the whole cube (
Heaven // Earth,
Sweltering Suns,
Realm-Cloaked Giant,
Flood of Tears, and
Nevinyrral's Disk), and they're all kind of medium/conditional/expensive (six if you count
Shower of Coals which is a pretty nifty card; great find!). I'm worried that even a mediocre aggro deck will run over the slower ones, though I could be very wrong about that. I really like how you've shifted 1-drops into the artifact section, but that tends to encourage people to durdle more, not less, which will exacerbate this weakness to aggro. What I DO like is how all of these choices encourage flexibility; again, however, this tends to lead to people durdling more and thereby not making the best choice at a given moment.
Consider the parable of Mark Rosewater and the Grizzly Bear. More choices means more agency, but it also means more ways to goof up. If you expect people to do well in those situations, this may be a fine setup, but my group would likely flounder and feel betrayed by their cards and their promise of setting up something cool if they'd had just one or two (or three or four...) turns before getting pasted by a deck that focused on playing to the board.
edit: I should answer the question. The thing about expensive spells is that some of them have to actually stabilize things or turn the game around. Here, they tend to not do that, either by virtue of being too small to risk in combat (
Angel of Sanctions) or by just not doing a lot on their own (
Scourge Devil). These sorts of cards shouldn't predominate, of course, as they risk giving major cases of the feelsbads, but I tend to like having some ways to "come back" from the brink of defeat.
*you've made me realize I need to look at my cube and reevaluate things like this. Blech. But thanks.