Evidently I spent over an hour writing up my response and didn't see this until just now. We both have very different definitions of roleplay. I think that's the root of our general disagreement.
Not a worry! I will be as thoughtful in my response as you were in yours. 
I do think that, preferences aside, there's a really satisfying discussion to be had on the relative merits of RPG design.
I would never design a character who is always assertive in any situation. It would neither be a convincing design nor would I expect it to be workable in any videogame. For me, the unvoiced PC is better for roleplaying, but I do not believe it or anything else can ever be perfect: there are some character designs that just don't work in DA:O, but I find I'm less limited in this respect in that game than I am in DA2 (a game which I love and where I have still managed to roleplay several unique Hawkes to a satisfying degree).
The difficulty I have with RPGs is personal, in the sense that my personality clashes so very strongly with the typical outline for a (silent) RPG protagonist. In a nutshell, RPG protagonists are (now) passive in respect of the plot or authority figures (basically, you typically run errands for people and otherwise accept quests, in a very "stand there and receive information" sort of way) but very active in their personal lives and personal relationships (i.e., shaping the views of people around then, actively surrounding themselves with particular people, etc.).
I'm the opposite: I'm very active in what would be "plot" or "quest" type situations (which often gets me into hot water), but actually pretty passive in my relationships (i.e., I will pretty much let anything that isn't an outright criminal offence slide and feel totally indifferent to it) and will be OK being around basically akin kind of person. It's why, for example, when I just when with my intuitive responses in DA2 I got everyone to max friendship by Act II. Well, aside from Carver, but he was a jerk, and I very much respond in kind to that. 
A voiced protagonist works for me because, as you said in a subsequent response, it makes it very clear under what limits I am actually supposed to be under. The Silent PC just makes it impossible for me to RP because it makes it impossible for me to know the actual scope of permissible actions in the game.
One example that sticks out in DA:O is the HN Male storyline. I was completely baffled, at first, by the inability to put yourself forward as a candidate in the Landsmeet (since you're basically divinely ordained by that point) or, more frustratingly, only being able to rule as Anora's toadie.
Nope, none of the explanations I put forth in my last post to explain the Warden's lack of a response were contradicted by Alistair's approval increase.
I did however put forth a scenario earlier in the thread where I stated that Alistair might have understood it was an insult but laughed anyway. I can see how that contradicts Alistair's approval, so I'll retract that explanation.
I wasn't very clear in my response, and for that I apologize.
What I meant to say, really, was that the internal monologue that you see your character as having is, to me, not really RP as much as it is just writing (and, since it's game related, a sort of exercise in fan-fiction). It has no impact on the game. And otherwise, I'm a very intuitive person, so I just don't think explicitly in that way. Thinking for me is more like... breathing? It's automatic. When I RP, I just occupy my character's headspace. I'm making choice for them, but not actively thinking out what they're doing, just... embodying them, in a sense.
All of which makes it very important, to me, to know what the limits actually are on what is and isn't possible in the game.
VO lets me know that.
And if my understanding is correct, your solution is to voice the PC so that the line can only be spoken in a friendly joking manner, meaning the Warden cannot be misinterpreted. That's actually a perfectly valid and sensible way to deal with the problem. However, I have another solution that appeals to me, which is to accept that the Warden can be misinterpreted. It just doesn't jar with me that an incredibly powerful speaker might occasionally miss the mark.
It doesn't bother me that the Warden can be misinterpreted. It bothers me that it's impossible to correct it. That's where I run into the problem, and that's what I think the conceptual difficulty with your position.