I'm the kind of fan who gets into these debates at 2 a.m. over cheap coffee and a stack of back issues, and here's how I break it down: Deathstroke brings peak-human-plus physicals, razor focus, and military-level planning. He's taken entire teams by surprise, dismantled squads, and in many runs he out-thinks opponents who are physically stronger. His combat efficiency — swordplay, marksmanship, and tactical setups — is consistently portrayed as elite. That means in a planned encounter where he knows his target, Slade has the edge on timing and lethality.
Deadpool, on the other hand, is basically the embodiment of chaos with an incredible endurance reboot. His healing factor lets him survive things most heroes can't recover from, and his meta- and comedic unpredictability make him dangerous in a different way. If a fight drags out, Deadpool can shrug off lethal wounds and keep going. For me, the cleanest conclusion is context: short, prepared ambush — Deathstroke. Long, messy slugfest — Deadpool. I always enjoy picturing them circling each other in an alley; it ends up being as much a personality clash as a physical one.