Nintendo is still treating Link as just an avatar for the player, but they have done too much with Link's personality at this point where it's not the same thing anymore. Link reacts to plot events and forms bonds with certain characters. That's Nintendo projecting emotion onto the player, rather than the player projecting his/her emotion onto Link, the player's in-game representative, as the story unfolds. Ocarina of Time was probably the first game to start doing this, but it was still the most transparent of the later Zelda games in this regard. By the time Twilight Princess came along, I felt like I was almost being told who, in the game, I should be growing more attached to. For example, I, as the player, formed a bond with Saria early in the game (the scene where Link leaves the forest for the first time still gets me). I was legitimately sad at times so I think Link as an avatar worked really well there. I felt like that was me feeling that, partially because Link shows no emotion so I felt what I felt almost entirely on my own. Alternatively, in Twilight Princess, Link is reacting and interacting with characters like Ilia and Midna. I don't feel like that's my bond with these characters anymore. I thought Midna was a pretty awesome character and there's clearly something going on between Link and Midna, but that's their story, not mine.
Not that that's a bad thing. It's not. My point is that Nintendo has made Link into his own character without officially making him his own character. I don't think they really understand why Link was mute to begin with anymore. They're kind of caught between trying to make Zelda more cinematic and keeping it in line with what it was in the beginning. The result is muddled. That said, in future installments of the series, Link either needs to develop a deeper personality with his own emotions, desires etc. (along with a voice) or Nintendo has to go back and re-evaluate why Link was simply an avatar of the player. I'm personally okay with either. I think it could work one way or another, just not with trying to be both at the same time.