Just to add, I tried to pay a lot better attention to everything during my second playthrough. Usually, with games like this, I don't really figure everything out until the second one, anyway.
Anyway, during my first one, I couldn't really stand Solas or Vivienne and I thought Sera was too weird. But, this time, I got to know them more by talking to them more. Solas turned out to be a lot better character than I thought. Sera, as well (those rooftop meals you can have with her were kind of cute).
I took Solas in my party nearly the entire time (first playthrough I always took Dorian). He's very useful, especially on nightmare. You get to know him a lot better from the party banter while walking around.
Another thing I noticed is....
....spoilers.....
after Blackwall leaves and comes back (if you rescue him), Solas and Cassandra are very harsh on him during the party banter. Like, I really, really felt sorry for the guy. They just shit on him left and right and he just takes it. Eventually, they lighten up on him but...geez...they tear him a new arse hole for what he did.