Dimir Control leans on cheap removal (Snuff Out, Cast Down) and counterspells, so Ultimate Alliance is excellent since its damage scales with your board and it's a one-mana Instant that punishes them for tapping out or committing removal to the wrong creature. Sprouting Renewal adds another proactive body and can destroy artifact or enchantment hate pieces the opponent may bring in — most notably Spreading Seas. Cut the slower card-selection pieces since you want to keep applying pressure under their counterspell suite rather than durdle. Play around Counterspell and Spellstutter Sprite by sequencing your cheaper threats first.