This thread makes me remember an ooooold joke article in The Duelist, about how they were going to ban Islands. The fact of the matter is, blue being the best color has been an in-joke of Magic for almost as long as the game has existed. I'm not saying it's right or wrong (and personally I think the other colors should be 'brought up to equal level' a bit)... But I think it's gone so far that it's almost an ingrained tradition of MtG game design by now.
Anyways, on to practical matters. I think banning "blue card X" is probably the worst possible solution to the problem, unless there is one card that is allowing an archetype to unfairly dominate (ie
Mystical Tutor or
Survival of the Fittest.) Banning, for example,
Brainstorm, would for one thing, probably not accomplish that much in the long run as far as balancing blue's power level. It would engender the ill will of many players, and blue mages would get by with
Ponder,
Predict,
Preordain, etc when they needed a cantrip. All of these cards see play already anyways.
Intuition is probably the most intelligent suggestion I've heard as far as a blue card to ban (as far as what would diminish blue's omnipresence the most without ruining the balance of the format (like banning FoW
would, for instance)), and I still don't think it deserves the banhammer.
I think far better solution(s) would be to start printing brutal color-hosers again (with the nastiest ones only affecting blue decks, and ideally providing a symmetrical effect so blue decks can't sideboard them effectively, ie more like Choke less like Llawan), and
most importantly WotC needs to find ways to print powerful spells in other colors. I truly believe that the problem right now is not that blue is broken or unfair; it's just the best color when considered from a wide perspective. This is because, for example, while blue gets effects like countering spells and drawing extra cards, white gets effects like preventing damage and gaining extra life. (The preceding sentence is a hyperbole, but you get my point.)
I think also, an important point to make is that there should be more powerful cards printed that are not so easily splashed into decks of another color. For example, if Tarmogoyf costed :g::g: instead of :1::g:, it would be much harder to just stick it in any deck where you need a dumb undercosted beater; if Dark Confidant was :b::b: then you wouldn't be able to just be like "well I have a low curve and I wouldn't hate drawing extra cards, guess I can justify a black splash with a couple sideboard cards."
I don't think that they should stop printing powerful cards that only require one colored mana, but if there were more incentives to play cards that required two or three colored mana, I think we would have a format that looked a lot less like "Blue, splashing x and maybe y."
Also, we just need some good blue hosers. And they need to either have a symmetrical effect, or not be easily splashable (in addition to probably needing them to be counter-proof.)