And also: similar to the issue that most people run too much ramp in green, most people also tend to bloat blue's spell section with card selection spells, and I think strapping more of that to bodies helps blue feel a little less like a 1-player game.
Just want to say I agree with the notion of sea gate being a control card rather than anything else, and that we tend to overload on card selection in blue.
I was a bit hesitant to post because of the controversy it would cause, but i.m.o. we tend to really overload on specifically
brainstorm, which is much more of a niche card due to environmental differences between cube and the two eternal formats where its really strong.
Brainstorms worth is connected to the density and availability of fetchlands; and fetchlands (or shuffle effect) based strategies will be niche in cube for the time being. In a 360 cube running the standard x2 fetch, x2 shock, 5.5% of your format is fetchlands, and each player in an 8 man draft should get about 2.5 fetchlands apiece. Fetchlands will make up around 5% of your average final 40.
Looking at mtg goldfish. The top miracles deck is 15% fetchlands at 60, RUG delver is 13%, RWU stoneblade is 15%, and bug delver is 15%.
Now, there is another eternal enviornment where brainstorm is legal, but fetchlands are not (besides
terramorphic expanse and
evolving wilds), and that format is pauper. I think every single person new to the format goes through a phase where they want to jam brainstorm into their decks, and its just not great. The only deck in the format that can use brainstorm as a card selection piece is the
thought scour running UB delver deck. The rationalization for brainstorm usually revolves around some combination of ponder or expanse/wilds as shuffle mechanisms, but at the end of the day you never really reach the eloquence, density, or efficency of running 15% actual fetchlands in a deck like you can in legacy, and brainstorm feels much more akin to how it felt back when iceage was released.
Brainstorm gets overevaluated in pauper as a powerful card precisely due to enviornments like legacy, and people miss that its a synergy card, for which they are missing an important density of a key part of that relationship. Thats not to say that brainstorm is a bad card in pauper, just that its a niche card, and isn't well positioned to be one of the defining cards of that format. Unlike say,
ponder or
preordain, which are actual independently powerful card selection spells.
I feel this applies to cube as well, where people feel the card is powerful, they want it to be a powerful card, it may be anecdotally powerful, but its much more appropriate to view it as a niche card, due to the limited access to fetchlands. If you are going to poach a metagame relationship from another format, you can't poach half of the relationship and expect it to standup in the new environment. This is the same problem that
stifle has in cube, and I would argue
wasteland has as well (though wasteland can be justified on different grounds, making it only overrated).
Now, if we cut shocklands, and just run a full 40 fetchlands, our players are getting around 5 fetchlands a piece, and their final number is more akin to what you would have in legacy, with your average 40 being about 12.5% fetchlands.
Unless you are looking to increase your fetchland density (and coincidentally I've seen some people here discuss precisely that), cutting brainstorm down to 1 copy shouldn't be too much of a loss. Most of you guys aren't running the really robust discard, self-mill, or tutor into play suites that could justify so many copies. I also don't actually think its correct to run multiple copies specifically to flip delver (even more of a vanishingly small % metagame relationship), or that its even generally correct to go out of your way to flip delver.
Even if we increased fetchland desnity, I'm also not sure that its even good to be running a large selection of these blue cantrips due to how powerful the effect is. At 360, I think its fine to narrow that pure card selection mechanism down to say 3 cards (maybe even 2), and than start attaching that effect to other more conditional bodies or spells that push people into actual strategies:
condescend,
sea gate oracle,
looter il-kor, or
jace, vryn's prodigy for example.