The companions need to do something in regards to the narrative. DA:O was actually atrocious for this. The companions never actually do anything and their relevancy is just railroaded plot - Alistair just happens to be what he is, Morrigan's thing is only possible because of Flemeth, and that's it for major involvement in anything. Even in their own side-quests they do nothing and wait for our input. That's weird and they start feeling like meat puppets for the player's enjoyment rather than equals in the narrative. I can't stress this enough. Controversial statement - DA2 is the best Bioware game in terms of narrative. Why? Because of its focus on characters who move the plot. Arishok, Varric, Meredith, Anders, Isabella and even Hawke in the first act. It went bananas at the end, but I expect nothing better from BW. Sadly, the bad production of everything else in the game means Bioware won't do anything like this ever again. This is exacerbated by the fact that players criticized it for the wrong things. There is nothing more frustrating than seeing people criticizing something you do as well, but are criticizing it wrong. Enough about that.
I don't know what else to say on the topic of companions really.