In that video review, around 7:30: "We see a lot of Dark Elves hate Argonians." "Still, it's been
a long time since Morrowind." (My emphasis.) ZOS has been saying the game is set in the Second Era for two years now, so this is a case of the reviewers not doing their research. They also misstate the RvR requirement as being level 20 (it's was 10 during that beta and still is), and apparently didn't know what time the beta ended (which was stated in the same e-mail that issued beta codes).
They do point out one significant problem with the game around 2:00: The quest phasing, which makes playing with friends, an important part of any MMO, very difficult. But you'd never know about it reading this thread since everyone wants to harp on non-gameplay issues.
As for the gate thing they mention near the beginning: That was keeping them in the tutorial area until they completed the tutorial quest line. ZOS has since changed it so the tutorial is optional, and this caused a lot of outcry on the beta forums about how it 'breaks the storyline'. So, ZOS can't even win on this issue. (I also like how the guy is complaining about the 'lack of freedom' unbecoming of a TES game one moment, then seems surprised how he can join multiple guilds (fighters', mages', etc.) the next).
And to be clear, the Imperials do not come with their own quest content or anything of the sort. For all intents and purposes, they are just an aesthetic and a set of racial passive bonuses (and RP potential).
From what I've seen both in previews, in-game and in the post-beta survey, characters who hit the level cap can change alliances as well. So I guess the only advantage the pre-orders get is not having to grind to the top before being able to do it.
It's not changing alliances. After completing your alliance's main quest line, you can travel to veteran versions of the other alliances and play through their quest lines in order to earn veteran XP.