Dragons are mucked by cover.
They cannot shoot through it.
They cannot move around fast enough to melee you.
Give me single stoneblock, a bow and some arrows, as well as the healing spell, and I can kill any dragon naked

Any enemy that cannot move at super speed and does unavoidable leap attacks can be killed by almost smart gameplay alone, and even they can be killed by smart gameplay, altough that's more in the bordeline of exploit.