Disrupting Shoal is a bad counterspell in legacy. Counterbalance is better because it's reusable, it doesn't make you pitch cards, and it has amazing synergy with card:Sensei's Divining Top. Other good and affordable counterspells are Counterspell and Daze . Flusterstorm seems weak because it restricts what it can counter and it doesn't flat out counter the spell, although it would be hilarious against storm combo decks, so I would suggest moving it to the sideboard in case you encounter such a deck. Eyes of the Wisent also belongs in the sideboard as it's only effective against blue control.
18 lands seems a bit low, you might want to consider adding more. If you run this many creatures, Ancient Ziggurat could fit in here. Other cards you might want to add are Swords to Plowshares and Lightning Bolt .
I figured shoal was similar enough to Force of Will that it would be a cheaper substitute. It's another reason whi I ran flusterstorm since I needed a 1 cmc for shoal. I actually do own Counterbalance so I can give it a try.