I blame this squarely on the origin character system.
Because all our companion needs to be able to serve as the protagonist, and they have to have the same plot motivator the main character along with their companion plot. This makes them double up on conflicts/forces.
If you took all the origin companions right now and removed their tadpole situation (and add some other excuses as to why they want to follow the main character), you'll end up more focused, traditional NPCs.
You'd also end up with the entirety of Act 1 (and possibly more) having to be completely gutted and start over in order to have something else function as the central narrative.
