Well, dwarfs have been in GH since it started, but goliaths are new. Dwarfs have several established kingdoms in GH, but goliaths don't. Dwarfs have had large amounts of text dedicated to explaining their culture, both in and out of GH-specific material, but goliaths haven't.
So there's three reasons why goliaths would be a problem.
Good thing I said "sentence or two" and not "paragraph, right?
I will state that even a novice worldbuilder should be able to manage one sentence on each of their PC species. Assuming that the worldbuilder is going for the D&D standard of each species being a distinct people with their own language and distinct culture, that is.
It wouldn't even be difficult. The DMG could present a few questions to be answered, such as "how do they feel about outsiders/people of different species?" with a few examples given such as "welcoming,""friendly but cautious," "wary and distrustful, but willing to keep the peace until provoked," "usually hostile at the get-go," or "demands they prove themselves through trials." There could even be a table to roll on or choose from, or to use as examples should the DM want to make up their own answers.
You are once again confusing worldbuilding with actual play. And funnily enough, you're actually making my point, except that because of that confusion you think you're not.
The writing in the world book or chapter or whatever--the book that WotC will be producing--will be showing how the Orc Empire is not evil (again, "not chaotic evil" does not have to mean "always good"; the orcs can be neutral). The DM will then, hopefully, show this in their own campaign by having the PCs interact with not CE orcs and orc societies.
Worldbuilding isn't telling because it's a different form of media from the actual play. It's a literary media, and more specifically, it's (usually) a wikipedia-esque listing of facts. If the entry on the Pomarj claims that it's not an evil empire, but there's nothing to support that in the text, then it gets a big fat <citation needed>.
Were a lot of people upset when Nentir Vale was introduced? I admit that I wasn't paying attention to anything D&D during the 4e years, but the reactions I've seen to it have been between "high praise" and "it's OK," with most being towards the "praise" end of the scale.
Would a lot of people be upset if this world was created for the sole purpose of being used as an example of how to build a world and wasn't actually turned into a real setting? I don't think anyone here is saying that this hypothetical world must be used as a new setting--just that it would be a good idea.
