And once they find the cure they may head to Weisshaupt if the player decides it (going by my suggestion). The point is that if the next game involves the north, then it will involve Weisshaupt where the UltSac Hero is bound to return in the form of the personalized tomb.
*MEEEEEPPPP* Wrong. You don't know that yet.
That's fine for your Hero, but the fact of the matter is that this storyline needs to apply to all Heroes. Some may like wild goose chases, but at least some would not. Therefore the quest must be a legitimate one so that all Heroes will participate in it. Also, the Hero who is queen indicates that she is on the quest because she strongly believes that the cure does exist and will help her and Alistair. The queen would not leave court unless the quest had a high chance of success. The Hero who is king would think the same.
And yet it could still fail. Even if the queen or king thinks there's a 99.9% chance it can still fail.
Correct. I wouldn't be letting the Hero go, but you would be. This solution meets the demands of both sides in this debate. You're also correct that I have no idea if BioWare will drop the Hero's story after this suggestion is implemented, but the chances that they will are much higher if the players are able to select an appropriate ending for their Hero's story. BioWare will be inclined to let the players have the final say, rather than contradict and overwrite them, especially if BioWare WANTS to stop bringing up the Hero and making games that account for every possible outcome.
I'll repeat what I said before because apparently you (purposely?) misread it: you do not know if Bioware is going to drop the HoF completely after DA:I, not after "your suggestion is implemented". If Bioware drops the HoF from the story entirely, player regain full agency.
Maybe they do advance the timeframe by 50 years. Even in this case, the Power of Blood Heroes can live for hundreds of years.
Where the hell do people get that idea from? And even if it is true, it's gonna get retconned.
I don't quite understand your disagreement here. Your posts look like this...
You: I don't want the Hero to ever return.
Me: Cool. Here is a suggestion that can stop your Hero from ever returning.
You: That isn't what I want.
Me: 
So... is it that you don't want anyone else to have their Hero return? Are you trying to deny other fans the opportunity to see their Heroes again?
*sigh* I'm going to be explaining this a lot, aren't I?
To sum it up:
Do I like my HoF? Yes.
So would I play the HoF if they returned? Yes.
Would I like it? Most likely yes.
Do I think Bioware is planning to have the HoF actively return? No, because they said so.
Do I think Bioware has the resources to account for all choices, personalities, romances and other tiny details to recreate every HoF? No.
Do I think Bioware currently has the writing capability to bring back the HoF and familiar cast like they were in Origins? David Gaider left so no.
Do I think it's possible for the HoF to return without causing a shitstorm? No.
Do I think it's wise for a company that's already bordering rejection from a large portion of it's core fanbase and suffering from EA-syndrome to take such a controversial and huge risk? No.
Do I think your suggestion is an exception in any way shape or form? No.
So do I want the HoF to return? No.