I don't get the massive up roar about the possibility.
If they are voicing the character and focusing the whole game around one protagonist as opposed to multiple possible variations that were previously possible is it not possible that they can make a better narrative to go with it.
We all know that Bethesda's biggest strength is the world design and their weakest has always been the story and quests system, coupled with how that combines with the characters progression in the game world.
With a fixed protagonist that is in terms of narrative an easy thing to work around they could in theory be able to tell a better story, create better character relationships and better world interaction without having to take a silly amount of other things into account.
Does it limit end user character creation ideas? Yes. Does it make it theoretically easier to tie Bethesda's previous strength of world design together with telling a bloody good story and crafting a better questing system. Yes
But let's also face it
This is a promotional video. The one spoken line was probably just for effect and the protagonist is just the default promotional character that all games have. Skyrim had the bog standard Nord Dovakiin and alot of people will never have even played with that style character (I didn't) so will likely not be forced on you.
People are taking a massive jump by coming to the conclusion that the character is voiced and set in stone as a young white male.
Put your pitch forks away and wait until e3 at least so you actually know what you are getting so upset about is even true