I've certainly used the feedback report to say that I'd like to see Velanna and Sigrun in there. Even if they never show up again, I'd like to have a record or their interaction with the Warden.
I think there's less point in adding Anders and Justice, since it just draws attention to the fact that it doesn't matter what you do in regards to them in Awakening. Anders always becomes a Grey Warden and Justice always possesses him, even if they never met in your game. That horse bolted more than three years ago, and there's little sense in closing the stable door now.
I feel that making some kind of closure in the Keep would be the best solution. Sure, it'd be a retcon to make some kind of final choice options (like removing options of giving Anders to templars/not-recruiting Justice) but it's already retcon even without them. At least this retcon would give clarity
But, eh, at least I hope they'll add Velanna and Sigrun. That would be good enough... I guess