So, what if Solas is the companion that sticks with you until the end no matter what? Considering his reasoning for joining the Inquisition and how important his knowledge is to the cause, I could definitely see that!
I have a feeling it will be Cassandra since she appears to be the one who first finds the PC. Her, or Varric if they continue the "storyteller" thing from DA2 (which I doubt, but hey, could be?). Still, I plan on having all companions with me until the end.
I may or may not have Morrigan running around in the Seer's vestements and a Circle mage cap in one of my playthroughs. She looks... surprisingly all right that way.
If only the game had the capability of companions commenting on stuff like that! I forget which game I was playing...Saints Row 3, or something?...but the PC would comment as you dressed them in different outifts ("oh, hell no!", etc).
I'm happy with the "companions retain their own personal look" thing, though. I like them maintaining a style that's distinctly them.