I think that Dwarf Monk would be even harder. The thing with elves is that they are like a weird bolt-on caster module for any class. An elf anything (where "anything" excludes Berserker) becomes a better caster than an a stock Wizard or Sorcerer. This lets you largely ignore your own class if you so choose. This is important in the case of Monks in the Cursed Oasis, because every... single... monster... is murder for you in melee, but having a strong fireball option lets you mostly bypass this. A Dwarf offers little for the Monk and offers no alternative to having to deal with poison, curse, and magic damage.
The boss, of course, is a different thing altogether, but I think the slight gains made by the Dwarf here are, uh, dwarfed by the challenge of getting to him.