This game is NOT an RPG. It is IMPOSSIBLE to rolepay

The downside of this was that the Warden was a blank-faced mute staring awkwardly at their conversation partners who couldn't even have expressions because they might have conflicted with the great range of possible personalities. I always thought DA:O was a pretty good example of why this kind of RPG is quite difficult to do when your characters are more than a little portrait in the corner of a text box, or a polygon/pixel block (in those games, immersion through graphics wasn't an issue yet). When the camera actually swings back around to the lovingly animated person pointedly not participating in the conversation they are supposedly having, it gets weird. If we could have that range of possible choices with appropriate voice acting and facial animations, that would of course be the dream, but that might be too much to ask.

ME:A was more for a DA:I style of conversation options, and I think that's a good idea because DA:I had a lot going for it. You usually had at least three distinctive personality types (friendly/jokey/aggressive-to the point) for most answer options and sometimes a 5 option wheel of different emotional reactions. Adding to that, you could put points in knowledge perks and unlock conversation options that way every once in a (rare) while and then there were class and race specific conversation options. All that made sure that the Inquisitors could really feel quite distinctive, even if you made the same basic choices in quests. ME:A just doesn't have that range and neither did the OT, but the OT at least had the feature that the two conversation options you had were usually very different and consequently painted very different pictures of Shepard, which you really can't accuse ME:A of most of the time.

I would have liked to have seen what this game would have looked like in the dialogue wheel department if they had gotten another year of development time to record additional Ryder voice lines and NPC reactions. DA:I had my favourite of the voiced dialogue wheels so far and I would have loved to have played an ME game with that level of choice and potential for mix-and-match. If we actually could have had all 4 options most of the time and logical and professional wouldn't have basically been the same thing, maybe with one of them being replaced with something more abrasive or hot-headed for greater role-playing potential, imagine how fun that would have been. As it is, it just feels like I'm looking at some sort of lackluster alpha version of DA:I's conversation system. At that point, just go full Witcher and don't even pretend the character is hugely customisable anymore, it'll make it look less like a frustrating inbetween.

For me, it was actually immersion-breaking at that point. If the whole dialogue had been text, that would have been fine, but if the other character is moving and animated and the voice actor is going for it, to have no reaction from the player character was odd, it took me out of the conversations and the roleplaying to see the Warden stand there like a zombie, giving zero indication of the detailed personality I had supposedly infused them with. However, that is taste because you are right, the roleplaying was more varied and I do miss that.

It's no more immersion breaking than voiced protags saying things that go against the paraphrase you selected, or auto-dialogue.

NOT a happy camper, let me tell you.

If Shepard ever actually reflected what I wanted him to be, it was a happy coincidence.

ME3 was a garbage fire, and not just because of the endings.

There's the thing though. If you compare Ryder to ME 1 or especially ME 2 it's dealers choice which is the easier to role play...but ME 3? not even close

I still don't see how I have more control, except to the extent that a non-voiced PC might have more lines available because unvoiced is cheap. All we ever have are the prewritten lines.

I wasn't bothered by that, probably because I mostly looked at the conversation partner during those scenes.  The issue could go away if they'd just do conversations from a first person camera.

Like I said, if you prefer it good for you.

I was right here (I mean, right there in the original BSN), fighting in the frontlines against it. 
And yes, they took away too much of our control in that game. You see, TIM was right, why kill dialogue options when you can control your character? Roleplaying is key for me.

Doominike , you are absolutely right, if the autodialogue happened a lot less and was more intelligent, I wouldn't have so much trouble with it. But it was filled with the most stupid lines ever: "The Citadel? The fight's here!" - "I'm here visiting a friend who got hurt protecting me..." (No, I'm here to see you Thane) - "Here, we have the key to finding the Catalyst and maybe winning the war, but we didn't give you until now because we weren't attacked" (asari councilor) ... "okay", and later "We didn't get the information, I'm sorry." - Trusting Brooks right off the bat... - Not being able to agree with the Illusive Man, or call on his bullshit at the start...
There are so many moments, oh man. 
Shepard's IQ dropped 40 points in that game (not that it was that high in the first two games, but still...). And LOTSB (in ME2) started a very sharp decline in dialogue quality, imo.

One of the worst parts of ME3 is the intro:
1) why am I here and why is that kid on a rooftop
2) who is this dude?
3) where's liara? Garrus?
4) when do I get control?
5) no, really, who is this guy?
6) kaidan? I thought I cremated you. Oh well
7) can I actually do something now?
8) anyone? This guy? Why am I supposed to know him? Liara? Garrus? Anyone? Even Jacob?
9) WHY AM I NOT ALLOWED TO CONTROL MY CHARACTER AND WHO IS THIS GUY
10) "We fight or we die?" I hope they don't complain about dialogue in a sequel after that little gem
11) Shep why are you running like a gorilla
12) shut up Anderson

And the only way was up from there really.

Silent blank slate gives more control over the PC's personality than semi-preset and voiced with auto-dialogue, period. If you prefer the latter that's fine, but you can't argue that you lose control that way.

Not really. If you find written lines more immersive and/or prefer the PC to be a mute, emotionless automaton that's your preference. Good for you.

Still that is not what the op is asking for. You gain some lines but lose so much expression. It's a compromise. It will always be a compromise but I don't see how how a mute PC is objectively superior for role-playing. I have been into role-playing for circa 35 yrs now and have done all sorts of variants on the theme. I have my favourites but I wouldn't call any of them ohjectively superior.