Imo, I would've prefered to stick to one character like in Mass effect trilogy because each time we have to go through dialogs about the lore, like if we were new players.
But, yes, that would mean that warden has not have to die on the archdemon and that possible since there were many other sacrifices like no letting Riordan die like an idot by jumping from the top of a tower, lol.
So after DAO, the warden will try to rebuilt the order (or at least help) wich will turn into the inquisition in DA 3.
DA awekeing will stay the same because we need a connection with Ander.
Then years later, DA 2, the warden will go to Kirwall to invistage about the corruption of wardens, meeting again Ander who will drag the warden into the war of mages vs templar. Hawke would be a companion instead of the MC because we need him/her to make the link with Corypheus.
Then in DA 3, the warden gone to the conclave because he/she was invited by Leliana.
Warden survived the Fade at the begining because he/she was used to it thanks to DAO.
Warden accept to help Cassandra build the inquisition by turning his/her order into it with the condittion to be able to leave when it's all finished because the purpose of the warden is to fight the evil demons.
We will still see Cassandra in DA2 because she is searching for Warden, a super hero who resolved the blight and "saved" Kirkwall.
The benefit of this fiction would be to get a consistent world with regular returning characters for cameos.
Also to be able to carry over the romance and see it grow through time or break because people have different opinions on different matters.
That would've letted us the choice to keep Leliana not hardened and just be in love with the warden for example or see a heartborken reunion with Morrigan where the warden will see his child, etc...
So for me that would've been so awesome to see a rooki warden getting power with each new episode until he/she become a real leader/ruler.
It's a bit annoying to always have a total new rooki every time. I usually don't mind but in this serie I regret to not have been able to keep my warden.