I personally think it's nice to see a couple returning characters in a sequel, so long as there are still plenty of new ones, and it doesn't strain credulity that the character is back. Like in DA:I, I was happy to have Varric back and it made sense that he would return, but I'd definitely be bummed if he was a significant factor in DA:D. It can be nice to have some anchors of familiarity amidst all the newness, it can help with maintaining a sense of continuity within a series. A sprinkle of the old helps to emphasize the new. But only if it's a sprinkle, otherwise the old starts becoming a crutch.
Well said.
Additionally, devs have to be careful bringing back past characters. Any such characters must be able to both stand on their own AND stand in the eyes of people who played the prequel games, which is no small task.
