Drowning is definitely worse than burning. With burning, your pain-sensing nerves get destroyed after a while and render you numb. With drowning, you are fighting for your life until that very last second where you grasp for one final breath of air and water comes rushing into your lungs causing you immense pain and collapsing your lungs. After about a minute of intense agony you'll lose consciousness and become fish food. So yeah, based on my experiences of getting a 2nd degree burn and extensive SCUBA work, I'm gonna say drowning is the worst because I've almost drowned once. It was, by far, the single most terrifying experiences I've ever gone through. And I've been in planes that have lost 5,000+ feet of altitude in the span of 5 seconds. Drowning is definitely the worst way to die (if you're conscious for it).