No.
And I want one of the following to return as a companion in the next game: Blackwall, Iron Bull, Sera, Vivienne, Dorian.
Personally prefer Dorian due to his successful reception by players (to the point that he may be the first not just 'gay' companion in DA, but the first homosexual companion that straight male gamers have gladly romanced!), and if we go to Tevinter... yeah. But with Gaider gone, that may not be the best choice.
I didn't list the rest, due to their inclusion in either previous games (Varric, Cassandra), or external media (Cassandra, Cole), or because of certain 'stuff' (Solas).
I like the trend so far (DAOA-->DA2-->DAI) where one character carries over.
I don't agree at all with moving the timeline down significantly.
1)This is the DRAGON AGE. It is HALF WAY THROUGH the Dragon Age. I don't want more than a jump of a decade or so.
2)While there is hints that this 'age' may be ending 'sooner than it should', and therefore any of the Chantry Ages may be an obsolete way of seeing the timeline, we still should have at least one game which acts as the transition to this new larger 'age', which still may be a 'dragon age', of course. (and no longer the chantry age)
Basically, I think your idea is pretty ridiculous. This may be the story of Thedas foremost, but that includes the characters. Cameos once in a while (as long as they're not of the fleeting and pointless variety) is no problem, and involvement of old characters in major plotlines is also quite cool.