Well. I've cleared out entire rooms with naught but a not-so-cheesy regular assassin/gloomstalker/fighter no problem. If you have movement speed and the ability to hide, you can solo pretty much the entire game without too much hassle. Most 'hard; fights have environmental advantages that can be exploited, multiple avenues of attack and escape and so forth. And that's *without* using the cheese builds.
well, if you have access to darkness or fog cloud, you can just hide there and the enemies won't even go searching for you (unless they are immune to blindness), so with hide as bonus action you can just peek out and take free pot shots at them. considering how most stealth classes get free access to fog cloud, larian is probably even aware of that.
