I agree that it is not the best designed encounter in the game and it will catch people offguard. But I actually like it for several reasons:
- Failing acutally has consequence and you are rewarded by an amazing cut scene for failing. So I encourage people not to win and look at the next point.
- Let's face it, save scumming IS a core mechanic of the game and you miss amazing content, if you are not willing to lose from time to time. So enjoy the ride and try again (or actually live with the consequence of failing, you can still beat the game).
- The encounter kinda highlights, that your enemies are no pushovers, they try to exploit weaknesses and have personal reasons for doing stuff. That encounter is crucial to the overall story.
- The encounter in itself is not very difficult, I did it first try on tactician, had more problems on later tries because the AI sometimes does really stupid stuff and dice rolls were against me.
A general tip: Most encounters really favor single target burst damage and not AOE, there are notable exceptions, but these are rare. If you keep that in mind an bring e.g. a paladin of any flavor, Lae'zel as a pure fighter, and either Karlach or Astarion, you will breeze through most stuff. If you respec Shadowheart into a Tempest Sorcerer she can also do insane burst damage.
