Originally Posted by
GtF
The matchup vs aether vial decks is kinda bad and if they get aether vial going it's very bad. Having EE main does help against merfolk.
Goblins I have found to not be that tough though, since stifle is really good against them and so is tarmogoyf. I play 3 blue elemental blasts in my board that I bring in against goblins, which helps as well. The version with black is a lot harder to beat because of warren wierding.
Against merfolk your general plan is to keep aether vial and standstill from resolving, drop a guy and remove some of their lords so that they just have a bunch of weak crappy dudes and can't swarm you. Obviously a lot has to go right, but I think the best approach is just having enough spot removal (and countering standstill, which is a real ballbuster). Nitewolf claimed he had success with umezawas jitte postboard but I think you'd have to be boarding into at least 10 creatures for that to be worth it.
Monoblue is pretty straightforward: disrupt them and get a quick beater out and kill them before their powerful but expensive spells get the better of you.
derfern: it definitely seems worth it to maximize your blue fetchlands if you are boarding in a volcanic island. Getting them with a verdant catacomb/stifle is cute and all but being able to cast your spells seems more important.
I don't think inquisition would replace thoughtseize because there are some spells you really want to be able to thoughtseize and I think overall the 2 life is worth it (force, moat, empty, belcher, ad naseum, tendrils, probably some others). But I could maybe see it getting played in addition to thoughtseize. And if your meta is only zoo and none of those decks that use the above cards, then feel free, but in an unknown metagame it doesn't seem worth it to me.