I'm curious where exactly it says the Redguards are black. Isn't it possible that Beth doesn't want them to be black but instead with that red-ish hue (hence redguards, no?)?
Somehow, I doubt it, considering that they weren't nearly as red in past games, http://images.uesp.net//4/49/MW-NPCs-Gentleman_Jim_Stacey.jpg, for example, doesn't look red to me, http://images.uesp.net/a/ac/MW-npc-Manicky.jpg. They certainly look like they were going for black, and I'm pretty sure their voice actors are black, so logic says that's what their supposed to be, and the skin color in Oblivion is a result of the discoloration characters sometimes suffer from and not a conscious design choice.
Redguards aren't "black." They aren't even homo sapiens. They're from a planet called Nirn that is not, in any way, shape or form, Earth, and is not populated by homo sapiens.
And yet said planet is populated by people who very much look like Homo sapiens, and talk like them, and behave like them, they even have cultures that are similar to humans on Earth, and they've been called both humas and men, things we call ourselves. If you don't want people associating your fictional races with real life ones, then don't make them resemble real life races. Since Bethesda chose to make Redguards, and really, all the human races in the Elder Scrolls resemble real life races, people are going to associate them with those races.
And really, that has nothing to do with anything, just because they're a fantasy race doesn't mean they don't resemble a real life one, it's clear that they DO, and if Bethesda intends their fantasy race to resemble a real life race, which they obviously did in this case, they will be expected to make them resemble their real life counterparts, to the extent that they're not explicitly stated to be different, so giving Imperials green skin, for example, would probably be pretty strange.
Yes. And Imperials are not Romans. Nords are not Scandinavian.
No, but they certainly strongly resemble them, just as Cyrodiil is not any place on Earth but shows environments which bear striking resemblances to ones that exist in real life. Certainly, they're not identical in every way to their real life counterparts, they're a fictional race that is similar to a real life one, so they can be different in some ways if the lore says they are, but to deny the similarities is simply foolish.
And back on the subject, the images we've so far seen of characters are all considerably improved from Oblivion, and while none of these show characters who are not Nords or possibly Imperials except in the background where we can't clearly make out the details, thus rendering them rather unhelpful, we can assume that if Bethesda can make Nords look good, they can do so for other races too, and it was said in the podcast that Bethesda is paying attention to making all the races look good and more distinct, so if Bethesda delivers what's promised, then I think we won't be seeing orange Redguards anymore.