I also suspect that they may have few qualms about dropping certain race options that they "feel" wouldn't be missed too much by the mainstream, such as "unappealing" races like Argonians and Khajiit, and may even extend to cutting some or ALL of the races of Mer as playable. After all, "Absent Aliens" settings for fantasy and science fiction are kind of a hot thing right now, and BGS sometimes likes to jump head-first into popular game design and story trends, though this one would likely generate chaos and outrage, and would even try and make the Elder Scrolls franchise into something it is not.
Then again, one can expect that TES VI will see people going into it from ESO, and since ESO did a better job overall at bridging the "visual and customization quality gap" between the ten races than either Oblivion or Skyrim, that potentially would build expectations for TES VI to improve on it further without taking steps backwards (like removing races or bringing back the quality gaps). Heck, even people going into TES VI from Skyrim are expecting improved customization options and less quality gaps between the playable races.
In case you're wondering what I mean by quality gaps, I'm talking about instances where certain races lack entire customization sliders that other races have, and often have fewer choices within the sliders they do have. Examples include how in Oblivion Argonians, Khajiit, Orcs and I think Dunmer had NO customization options for eye color of any kind, and how Argonians and Khajiit virtually always have far fewer "hairstyles" than the other races (and in Skyrim's case, the Argonian "hairstyles" were all pretty much made with less than a handful of modular parts). I mean yeah, I get that certain races are less important than others in regards to the world building, but it does get a bit ridiculous when certain races practically get the vast majority of customization options while a few might get nearly zilch in comparison, especially the case with Oblivion. They ought to consider expanding the character art department here so they can have the ten expected playable races without such a large gap in customization options.
So no, I'm not particularly enamored with the idea of a voiced protagonist in TES due to the distinct possibility of them axing race options to get them in, which has the potential of losing the Elder Scrolls feel, even more so than that TES card game for iPad and PC which is kind of an odd choice for a spin off. Race axing would likely end in a disastrous social situation not at all unlike the one that happened recently. IF they do it WITHOUT axing race options for the player, than I wouldn't care about it as much. Silent, mute or "possessed" (maybe it could have something to do with the act of Sword-Singing and use the voices of fallen warriors before you or something, I don't know if that would really fit the lore though) would be preferable choices for TES in my opinion.
None of this is to say that I don't think BGS understands the importance in having the ten playable races, either. It's just that it's VERY hard to tell what they are thinking about regarding stuff like this, and it's frustrating to not know until a few years from now when they possibly reveal TES VI.