1- The abductions shown in the cinematic intro aren't supposed to be happening in BG, but in the surrounding region away from the city.
2- I expect our first arrival at BG to be something that the game wants to surprise and awe us with. A "crowning moment" for our previous efforts during the campaign. Starting a tutorial sections there would dull the moment (and the impact of that moment) considerably.
Yes, that's why I made the Goblin example, assuming that would happen outside. I know that abduction can't happen in BG. Having players leave Baldur's Gate thinking they go on aregular adventure. And what and adventure it's going to be.
I think the tutorial should be slower and more believable, where it happens I don't mind so much.
Agree though that Baldur's Gate should be a moment of awe. Just as Avernus or a spelljammer should be. Giving all of BG "away" in the beginning would lessen the experience though, for me included.