I'm afraid the story will be just rank average or even worse. Main reasons for this:
1)The already poorly written evil/stupid plotline, and the plot armor shielding the player from fail states due to their stupid-evil choices, will manage to worm its way into the main plot even on a good walkthrough. Meaning, the story will turn into a convoluted mess of suprise twists that make the tadpole a harmless/pragmatic source of power and a constant "companion" you can't get rid of until lategame, or in the sequels.
2)The world will be a streamlined, mostly lifeless theater set with little feel of exploration and lived in environment, even in urban environments. I wouldn't put it past Larian to resolve compounding problems of accounting for player choice by killing off scores of NPCs and the companions you discard. Maybe they'll resort to the already mentioned DOS2 plot-twist, where the city of Baldur's gate is already under siege when you get there, to achive this.
3)The game releases with the narrative mechanisms still buggy and poorly implemented: You don't even know if you're on the clock or not with the tadpole, companion storylines fail to proceed due to them being tied to long rests you're actively avoiding due to RP purposes etc.
The promise of being led to death is reason enough to follow.
