Roger is awesome.
He is, indeed.
Parenthetically, he was an sf fan and active in fandom as a youngster; I suspect that if he's particularly frustrated by the nonsensical noisemaking occasioned by his giving Thor a fair and good humored review it's partly because he understands the mentality of the self-professed aficionado too well.

What's a realm? Are the nine realms different parts of this universe? Or are they nine different parallel dimensional planes?
As far as I could fathom, the movie doesn't really say...
Now call me a fucking idiot. Slug me right on the chin.
Of course not. It's folks who think that such trivia bears on the quality of a story who are "fucking idiots." It was enough, for me, that Thor's explanation to Jane occasioned using the myth of the "world tree" in a charmingly allegorical fashion. That was visually clever - "neato," as you say.