1. You are entirely passive in WotR. You see it happening, get one shot off and fall into a crack to deal with "mundane" things. Granted you are not all that active in BG3, but you run around the ship and i the end intervene in the fight between a mind flayer and a high ranking devil. After that the expectations are higher.
2. The story flow in WotR is better. You see the "epic" demon invasion and once you emerge from the sewer the big slaughter is over and you have to deal with the rearguard of the demons, fighting undead and cultists, helping the resistance, ect. Its all connected.
In BG3 you have the beginning with the mind flayers, devils and dragons. And then the story suddenly stops and gets shelved while you help out druids agains goblins ect. Typical beginner adventurer quests which have 0 relation to the start you experienced. Even the tadpole gets "disarmed". Why have this epic beginning when its not build upon? Thats probably why people feel it is so out of place. Because objectively there is no difference in how epic both games start. WotR just uses that premise much better.
