1) With a new PC, the story could be about almost anything, as long as it stays in Thedas. With a returning PC, especially one who's a blank slate light the HoF, I would the story to fit well with the
PC, to be connected with events of the previous installment. I don't think it's impossible, just unlikely.
2) And I'm saying I'd rather the story really fit the Warden if the Warden was to return as the PC. Not just, tossing the Warden into this new unrelated conflict, because he's so awesome or something.
(I hope you don't mind I've enumerated your quotes just so that I don't make a whole speech bubble for a single line and so that you know which points are directed to which of your own points. I have bolded them just so that it is made distinct that I added them and that they were not part of your quotation)
1) This is true but as we saw with the Inquisition example there was nothing hindering the Warden from, say, taking the place of the Inquisitor (though to be specific it was found that there was nothing preventing the Warden from exploring the themes outlined in DA:I). Actually your argument could be carried further; why allow returning instalments (not PCs but labelling the next game as DA:something). Could it not be said that it would be best that a brand new franchise be made for every theme one wishes to be explored? Of course this is an absurdity, I mean to show that there is nothing preventing the Warden, as also in the lore of DA, from exploring new themes.
But you raise an interesting point regarding connections with previous instalments (I assume heavy connections in this case and not something like "oh hey Ludwig was a companion in the last game and now he's a companion here too"). I would say though that this is not the best way to execute the goal of 'world exploration', if we agree that is a stated goal. I would go so far as to say that it is an artificial restriction to say that there ought to be a connection regarding events to past instalments.
I sense that you are making the argument that future games with returning PCs must have something to do with the events of the past instalment. Not so I think. In fact I want to show the example of the Witcher series; what connected Witcher 1 to Witcher 2 in terms of events? I seem to recall something about a drug cartel and the end of the world or some such nonsense occurring in Witcher 1 while Witcher 2 had you hunt the King Slayer who had you framed wrongly for a crime. What connected the two was not the events it was the characters. The same characters (companions) we see carried through the DA franchise, though half-assed may I add, without the central tether (returning PC) tying them all together.
2) To this I ask you what event ever occurred that was so perfectly suited for the people it ensnared? Let's try the converse; which characters were ever so perfectly made for an event or circumstance? Only the most boring! This is what would make a game absolutely uninteresting. If you are so perfect for the role then there is no deviation, no wiggle room, no room to define your character, something which is touted in this franchise and by Bioware at large. I am making the point that events that give rise to such interest, comedy or tragedy, among other things, occur precisely when one does not fit them and has to make do.
If I may I would like to add a tangent point mainly; the above is what lead to the boredom I found within DA:I regarding the Inquisitor. He fit the themes, role, and events perfectly...too perfectly. He was just as a prophet should be with no room for hatred, bigotry or faults; a DA:I equivalent of Jesus. Heh now I have a strange feeling to replay DA:I as Jesus, more fitting though would be RNJesus. Yes...that will be his name: RNJesus Trevelyan, bestowing masterwork schematics to all the huddled, yearning merchants who seem wholly incapable of producing just the right one.
3) Well, remember, I picked this option:
"Though returning PCs and new PCs may be equal with each their merit and fault, I think in this particular scenario new PCs would fit better because..."
So, I agree that in some scenarios, what you are stating you want here would be interesting, make sense, and when planned ahead well, not have a high probability of contradicting my character's previous motivations. I disagree with regard to the Warden.
4) The end of ME1 teased Shepard's continuing conflict with the Reapers. With the ending of Witch Hunt and the Eluvians, it teased more of Morrigan, Flemeth, and the nature of the Eluvians. There wasn't really that strong of a connection between the Warden and the Eluvian, unless I suppose the Warden followed her, which only one of mine did. And it one case, it wasn't the HoF that tracked down Morrigan, 'cause she was dead.
5) And the difference between the Warden returning and some companions returning, is that the writers can continue to develop the companions, have them go through an arch or further explore their back story. 6) I don't want BioWare to further develop my Warden, and given that the major conflict in Origins was resolved, 7) I'm not particularly engaged with the idea of continuing to roleplay my Warden, or the Orlesian Warden if the HoF is dead.
3) True but note that when things are planned ahead well I dare say anything will be made well or executed to a remarkable degree. Why not start now?
4) The conflict was more regarding the Reapers, the only connection to Sheppard was that he was the only one willing or capable of doing anything about it.
Regarding DA though It is still a strong point I think as there was nothing, to my knowledge anyway, that strongly required the Warden (or hinted at something similar to the Reapers) to return after DA:O even though it could have been manufactured afterwards in the next game. But, and there's always a but, this game does tease the conflict with the blight, the link it has with the Maker, and the Calling. Would you now say then that the next game ought to be about the Warden and the Calling? (we'll say here that the Calling refers to the blight, the darkspawn, your oncoming demise and the Maker link just to put it all under one umbrella similar to how the Reapers encompassed the protheans, star child, synthetics and other such concepts).
5) Here I want to argue that the task of developing companions is most easily achieved and actually favours returning PCs. Why so? Well note if you had new PCs but with old companions, how would the first X hours play out? "Hello Morrigan my name is ____, so what do you do for a living?" Even though from the last game we know what she does for a living we are forced in this game to redo that conversation because we have to; it's a new PC that cannot be assumed to be telepathic or omniscient to glean through the past instalment to know the answer. However with returning PCs that already know Morrigan and have found out what she does for a living we can now move on, use X hours and build on her character. We may now ask more intimate questions that would be restricted from new persons or PCs. Now this argument that I have made would fall absolutely flat if new companions were made but you made the point that "the writers can continue to develop the companions, have them go through an arch or further explore their back story"
6) Sure but the major conflict in Origins was similarly solved for Morrigan, Leliana and Anders why then are they allowed to have new conflicts of their own but not the Warden?
7) Aha! I've got you here! You say here that you are not interested in continuing the Warden if they are dead yet you mentioned above that they can explore the backstory or character arch of past companions even though they too may be killed in DA:O (you mentioned that your Morrigan died specifically). Are you similarly no longer interested in building up their character because they may be killed?