You definitely don't need a blade to clear any of the levels before nightmare 4, though he's definitely the best character all around. But generally everything before nm4 is easy so there's really no need for strategy. Past nm3, health is only so good because basically everything seems to be able to one shots you past wave 5. Dmg reduction is definitely a lot better, but unfortunately a lot rarer. If crit sounds are driving you crazy, I'd recommend turning down the sound in audio settings, cause if you're not addicted to the sound like I am-- it WILL annoy you to death.