UW Control is light on creatures and heavy on sweepers (Supreme Verdict, Temporary Lockdown) and counterspells (Dovin's Veto, No More Lies, Spell Snare), so Hearth Elemental's creature half dies to Supreme Verdict too easily and Get Out has few good targets. Colorstorm Stallion is a strong threat with ward 1 and haste. Ward taxes their targeted removal, and its mana value of 3 means Spell Snare can't counter it. It also gets +1/+1 each time you cast an instant or sorcery, giving you a clock before they stabilize. Negate answers their noncreature spells like Teferi, Hero of Dominaria, Temporary Lockdown and Memory Deluge, but it can't stop Supreme Verdict, which can't be countered. Ashiok, Dream Render exiles their graveyard with its -1, which shuts off the flashback on Memory Deluge and Plunder the Trollshaws while it pressures their loyalty-based plan. Keep Stubborn Denial as a cheap counter to protect your threats from noncreature answers such as March of Otherworldly Light and Get Lost.