I’m on Act II in balanced difficulty and haven’t suffered a total party wipe yet. I also don’t use any of the cheese bombs, arrows or poisons but I have no issue with those being an option in the game.
If you’re not using Bless or gaining advantage in combat you’ll have a harder time.
And if poor rolls meant I had to murder La’Zael at the start of the game so be it. She was obviously meant to die like all those poor innocent deep gnomes.