I think it makes things interesting when the companions are passionate about something, even if I don't agree with it. But I tend to like carrying around companions that are going to gripe at each other the whole time (Hi Alistair and Morrigan; Hi Anders and Fenris). I already know my Dalish Inquisitor is going to have no love for templars or the Chantry, but not to the point of being unreasonable. His own agenda, the personalities and agendas of the companions, as well as unknown factors in the story will naturally be taken into account. ...That said, I admit that I'm hoping for an excuse to grouch at Cullen... 
I agree, especially when companions start bickering between them and not just at yourself. Makes the setting livelier
But don't be too hard on poor Cullen. There's a chance he already has his life screwed by two of our avatars.
Wonder if companions will mention different things depending on your background. For example, related to this thread, will Varric tell a Dalish Inquisitor that he met Merrill in the past?
Varric: "Did I tell you that I met this nice Dalish mage not long ago? Her name was Merrill"
Dialogue choices:
1) "Merrill? Sorry, the name doesn't sound familiar to me".
2) "Merrill? Ah, yes, the misunderstood scholar who tried to improve our knowledge of ancient elven relics".
3) "Merrill? Ah, yes, the stupid pariah who (almost) got her whole clan killed".
4) "Merrill? Ah, yes, I have it in my pokédex... Sorry, I thought you were saying 'Marrill'"