As someone who has had very little exposure to both WH and WH40K as a whole can anyone shed more.....details on what we can potentially expect from this? Naturally you won't know as you're not the devs but this was not a setting I expected to see. I guess my first burning questions are:
1) It seems RT is a completely separate setting from the actual 40K mythos? Yes/No? If yes, what exactly makes it different from what 40K entails besides it just being.....ya know full of traders and money rather than armies and weapons? Is that the only distinguishing feature?
2) What kind of class system (as well as races) can we expect from this game? Assuming it follows along the lines of other digital cRPG rules that we've seen these past 25 years? Are there only rogues? Are there soldiers? Medics? Faction Leaders? Anyone whose actually played the game able to shed more light?
3) From videos I am seeing can any galaxy race be a rogue trader? Or is it only humans? Seeing a lot of humanoid only race pictures when looking info up.
It's going to be a little difficult to wrap one's head around Rogue Trader if all one has been exposed to is the wargaming side of the franchise. To put it into real-world terms, Rogue Trader is like the discovery of America where you are the explorers, setting out to bring civilization and religion to the heathens (or murder them all if they resist), trade with (read: exploit) the natives, and enrich yourself in the process. All the while, you are in the possession of a ship (or a fleet of ships) that the people you encounter can barely even dream about.
To put things into perspective, the Rogue Trader RPG was the first game where Fantasy Flight Games outright ditched the concept of tracking the players' money. Money is almost irrelevant to a rogue trader. You are so filthy rich from the very beginning that you start having to buy at scale before you might not be able to pay for something. Buying a single lasrifle is a meaningless expense to you. You probably don't even know what it costs or what those numbers mean ("how much could a banana cost? Ten dollars?") Equipping a whole company of soldiers with lasguns is more like it, and even then, you'll probably leave the details to your retinue of accountants.
To answer your specific questions:
1) RT is the regular WH40k setting. The main difference is that it primarily takes place outside of the borders of the Imperium of Man, and your character's words are expected to be followed as if they were the words of the Emperor himself.
2) There are many classes, and they are of a grander scale than you might be used to. You're not just a soldier; you're a celebrated war veteran who leads armies into battle. You're not just a spy; you're a seneschal who employs hundreds of people who report directly to you. You're not just a pilot; you sit in the plot chair on a massive starship with tens of thousands of crew, issuing commands to dozens of lesser officers and even other ships.
3) Rogue traders have a lot of... leeway when it comes to the rules of the Imperium. If they want to have nonhumans in their crew, they can. Possibly. Until they return to the Imperium, anyway. It's not unusual for rogue traders to employ nonhumans, particularly Aeldari or the lesser races like Kroot. But rogue traders and their crew are, typically, human or servitor.