I had the same feeling, act 1 is perfect, with interaction with the companions at all times and several unique scenes. As the game progresses they fall a lot and in act 3 there is almost no interaction with them. For me, the game's difference is the interaction with companions and the romance. I would like additional scenes in act 3, especially for the romances.
At the end of the game, I was very disappointed, I spent 125 hours on my campaign, I used Gale throughout the game from the beginning, I developed romance and in the end he barely spoke to me and left... I felt cheated by him and completely dispensable.
Apart from Halsin's very basic speech and others who only had one line of speech.
For me, this game is more about friendships, romances and adventures that we develop with our companions, but this was not reflected in the game's final scene.
