Well I'd hope Dorian for a very specific reason: I want to see the next game centred on the Imperium, because I really want to see that place. And so having Dorian in it would make a lot of sense.
I pray to God, Buddah, Toutatis, Jupiter, Athena, Anubis, Itzamna, Thor, Hubbard, Unkulunkulu & Neil deGrasse Tyson that it won't be Sera.
That aside I like my Cassandra. And I wouldn't mind to see Cullen as a companion (finally).
As for the rest..
Iron Bull is totally the kind character we see once, like Oghren (I consider Origins & Awaking as one, same generation of Dragon Age if you will), and honestly in this case rightfuly so.
Solas , I wouldn't be suprised if he becomes the baddy in an expansion & dies before we see 4. Let me rephrase that, I HOPE that's the case. The potentially tragic villain.
Vivienne, meh.. and she's probably too busy with her own agenda.
Cole.. I honestly got so tired of listening to his gloominess. So rather not.
Blackwall, I mean, you know, he's kinda like a doggie, a labrador, so maybe he'll be a summon like the mabari in DA2.. hehe. Anyway, I just don't there's much left to his character, you've got him pretty much figured out 100% after the first 10 minutes.