I'm not sure why people think a smaller number of words plus a tonal icon works better (by "better," I mean, having the player understand what their character is about to convey and how they are about to convey it). I mean, yes, as I've said a number of times, "anger" as am emotional tone can mean several different kinds of accompanying facial expressions and body language, and it's not like the presence of the angry icon lets us know for sure what we're about do do physically/emotionally (apart from what we're about to say.)
For people such as myself, when the wheel first came in in Mass Effect (before I started working at BioWare), is that I was already picking dialogue options based on their tone even when it was full text.
If the situation was cordial and I appreciated the person talking, I picked the lines that came across as friendly. If I was mad, I picked the lines that came across as angry/hostile. The words used were actually not relevant beyond helping me determine the nature of my response. I was always bound by the restriction of saying what the game designers allowed me to say, and bound by any inferred sarcasm that they implicitly put into the line.
Speaking personally, what I like about the dialogue wheel is that I actually watch my character speak and say and do stuff. Obviously this doesn't work as well if a player wishes much stronger control over the specifics of the response, but that I can actually enjoy seeing the responses play out. With a full line of dialogue, I find I get stuff like this less often, and I do enjoy that sort of stuff. I like watching the scene play out, which is also something that I do less of with full written responses.
In fact, for games like Alpha Protocol (which was even more condensed than anything BioWare has done, but is probably my personal favourite conversation system in any game) and Mass Effect, I often don't even play with subtitles on because I prefer to watch the scene play out.
I feel the main reason I prefer this is because I go into a PC game with the understanding that the conversations will innately not be able to precisely represent my character. I think it may also be because many of the earlier RPGs I played, like the Ultima games, were based exclusively on key words so I had already had no reservations having no control over the precise words I used, but I could from time to time pick keywords that displayed a particular intent.
Having said that, I do understand your perspective. I imagine the amount of control we're willing to give up differs quite a bit, just as I feel the amount of control we feel we're ever actually provided probably doesn't line up. I'm not sure if the positions are reconcilable, however. Sometimes the lines the player character can speak get very, very long (an advantage our current system provides). They also sometimes, structurally, get spread out over several lines which provides some additional challenges to simply showing the full line than simply clicking a button that says "show full line."
In general I see pros and cons to either, and in both cases neither is really a significant enough yay or nay over the other. If you were to force me to choose, however, I do like the dialogue wheel system more than full lines of dialogue. I base this more on games I played not as a developer, so I'm omitting DA2 and DAI from this consideration, but included Alpha Protocol and the Mass Effect games, as well as Human Revolution and so forth.