I think that against combo matchups, we have to pray to be lucky and not lose before we could disrupt or win. The occurrence of combo decks that are faster than Elves is few in number, and fortunately are being pushed out of the metagame by Canadian Threshold and its ilk. This also has the side effect of improving Elves' matchups in the metagame since decks such as Tempo generally have a difficult time with both Glimpse combo and Vengevine beatdown.

I'm not trying to shoot down the idea of Brainstorm + disruption if it means improving some matchups, but when the said matchup is Combo, and we're still only able to get ~50% win rate against them with such drastic measures, then it's probably a lost cause.

An alternative could be to play Orim's Chant/Silence against such decks, which serves as a proactive measure and is on the same color as other available sideboard cards (Gaddock Teeg, Absolute Law).