I'm having trouble understanding the "way to rip off Tolkien crowd." The only real similarity that I can find is that the Fallen were created by powerful beings by modifying the natural sentient beings of the world - a parallel to most of Morgoth's/Sauron's forces being tortured mutations of elves, men, ents, etc. However, that people are complaining about that now would be silly, considering we've had that particular piece of information since pretty much the initial announcement of the game.
The Urxen look almost nothing like the goblins of Tolkien's world, and if Brad hadn't mentioned that they are sometimes called goblins I doubt anyone would really associate them with goblins, at least not Tolkien's. The Resoln, or "wraiths" - what makes a wraith? Do they have anything at all in common with Tolkien's besides the name? All we know about them is that they have pale complexions, and as far as we know that might be all they have in common with the stereotypical notion of a wraith!
The Ythril look completely unlike any Tolkien-related artwork I've seen. They stand out to me as having the least human-like form (their hips look like they're set pretty far apart. They look like they'd have crazy lower body strength. The Magnar look noble, intelligent, physically powerful and huge in stature, with some reptilian features. They don't look particularly cruel, malicious or slow-witted, and as such I can see no meaningful comparison to anything in Tolkien's world...
The Kraxis... I can see the comparison to the Easterlings in that they are both human groups on the side opposing the majority of humans. And that they both originate from "the East." Comparison ends there, and that's a pretty superficial likeness. The Easterlings are an aggressive and relatively primitive race of men that submitted to the will of a powerful evil being. The Kraxis don't appear to have subtmitted to any higher power, but to have made a practical allegiance with the Fallen for the sake of survival. If you found yourself on a continent alone with 4 hostile races, and all your friends across the sea, would you fight? Or ally yourself with your new neighbors. The Kraxis chose the latter, and whether out of survival, greed for power, or whatever, they don't serve any analogue to Sauron (as far as we know).
Likewise, we don't know if Fallen = Bad, Kingdom = Good. I get the impression that Stardock is trying pretty hard to prevent that from happening. And if they succeed, then the fact that the Kraxis didn't align themselves according to race becomes even more meaningful. I agree it would be pretty boring and overdone if the evil men go and join the evil monsters because... well, because why? What would they actually have in common? Maybe a desire to rule the world, or destroy the world, but the former wouldn't imply a healthy alliance, and the latter is trite.
If Fallen = Bad and Kingdom = Good, I'll be sorely disappointed, as will most other people I think.
This can be fixed with some game mechanics that create an actual difference between Kingdoms and Empires; and that actually make Empires "unnaturals" have some trully unatural quality other than simply starting with a Death Magic Book. Whooptido, Mr. Bluebird is sitting on my shoulder. Give me an in game consequence for being unatural that will pervade my choices, make me truly understand that I am not truly in sync with the world.
And what makes you think they aren't planning to differentiate the races beyond cosmetics? To quote from the Kingdoms thread:
While of one species, each race is substantially different from one another in terms of culture, capability, and philosophy.
Straight from the horse's mouth. Not to mention that Stardock has stressed from the beginning that while there would only be two true playable races (not including custom content), the factions would nonetheless be as diverse as if each were its own distinct race.
To look at some concept art and say "boring! they're all the same!" or to make off the wall comparisons to fantasy from other stories (again, based purely on some concept art of sovereigns), is pretty short-sighted and makes more assumptions than most people would feel comfortable if they would just take a moment to actually think about what they're saying.