To me it depends on where they go with the story, and I already have my opinions on where they'll be going with the story.
Basically if you ask me the story can't be a sequel to the original series no matter how far past the events of the original series they place it. The endings create three VERY different galaxies, despite all those complaints about how they all felt the same.
If you go with Red the Geth and Reapers have been wiped out.
If you go with Blue, ParaShep's benevolent will no rules over the Reapers as a Galactic Peace Force.
If you go with Green, the galaxy is united in one gigantic utopia of peace and happiness in which all races share a common form of existence.
They'd have to retcon WAY too many things from the original series and that would likely just piss people off even more. As such we'd be looking at prequels, where I believe the realm is MUCH more open to possible stories.
If humans are going to be involved at all - and I don't see why they wouldn't be - then a good place to start off would be the First Contact War. Unfortunately this was a relatively short-lasting war, but the good news is that not too many details are given about it other than "it happened" and a lot of war vets in the original series were part of it. This, however, would limit the race selection to just being Human once again, but they could do it. Place you in the shoes of some special human soldier assigned to carry out missions against the Turians. However that would likely make people feel like it's "Just another Shepard" as the similarities between the two characters - even if just on a basic level - would be too similar to ignore.
Or they could go with a story set somewhere between the First Contact War and the events of the original series. Personally I think this would be their best shot. They wouldn't have to worry about retconning anything from the original series, and according to some of the people you talk to in the original series (such as Jacob), there were apparently huge threats to galactic stability happening all the time, the public was just never aware of it. As such they could easily just come up with any kind of story they'd like and stick it somewhere in between the First Contact War and the ME trilogy. Seeing as how after the First Contact War humanity has officially been "introduced" as a peaceful member of the galaxy, it would open the game up to possibilities of race-selections for the protagonist. In the first game the council explains how the Spectre's aren't their only tool, that they often use smaller squads for more subtle missions since Spectre movements tend to bring a lot of attention. You could be a member of one of these task-forces and thus be able to pick what species you want to be (I'm just spit-ballin' ideas here of how it could work).
Really the only other way I can see there being race-selection would be to go BEFORE the First Contact War, but if that's the case then you'd be cutting humanity completely out of the picture since they haven't developed ME technology or even opened up their own relay. Place it in the Rachni Wars or the Krogan Rebellions (I think the Rachni War would be more ripe since it was essentially a united galaxy - including the Krogan - against a common enemy).
Anyways, those are my thoughts on the matter. In short: I think the race selection option will be depending on where they place the story.