Here's a pro and con's list of a returning inquisitor. Got all the points trying to be made that I could remember
Con: The inquisitor isn't coming back they only have one arm.
Pro: Prosthetic.
Con: Not realistic.
Pro: Fantasy game.
Con: Starting at level 1
Pro: Prosthetic gives an excuse to go back to level 1. And you go back to level 1 as a new character anyways so why is it a big deal?
Con:Financially unrealistic (This gives a double con.)
Con: Spending money on a mediocre game that was limited by financial burdens. Because if they can't do something they've done with another series (Mass Effect) and tried to with this series, how can they be expected to make their next game any good?
Con: Inquisitor is boring
Pro: The game is about Thedas anyways so who cares?
Con: The game is about Thedas returning protag makes it about them. (...ah....what?)
Pro: Inquisitor is boring so its doubtful they'll take the spotlight
Con: But its about thedas!
Pro: What better way to express that than to have someone whose not native to tevinter go in and learn about their culture.
Con:Returning LI's
Pro: You got Solas and Dorian returning anyways. You had Alistair, Morrigan and Leliana all come back. And had Zeveran in Da2 and Alistair. And had Lelana in a DLC.
Con:Conflicts with new LI's
Pro:That's what the keep is for. Make it so your inquisitor didn't romance anyone. Replay-ability value right there.
Con: Want origin stories.
Pro: Yep. That would be cool. Probably not happening. But, who knows?
Con: Inquisitor only has the solas conflict
Pro: Inquisitor has that and the fact that they aren't well received in tevinter and probably have alot of them conspiring against them, thus dragging them into whatever issues Tevinter has.
Con: But they don't have any reason to be apart tevinters problems.
Pro: That's why its a story... you get to find out their reasons and how they get involved. Just like you would a new pc.
Con: I have no feelings toward Solas and could have him taken out by anyone.
Pro: Then what's the problem with the inquisitor doing it?
Con: but I don't want to play the inquisitor
Pro: Oh wait no... my bad that's con. Con: Why not?
Con: See reasons above.