For american XC, yes, golf courses and similarly "smooth" courses reign supreme. That doesn't mean that's true cross country, that is just what we happen to run cross country races here.
As for "intentionally extremely muddy" at NXN... wouldn't it only be "intentionally extremely muddy" if Nike were hosing down the course every year to make it that way every year? There are years where the course is in pretty good condition (in regards to mud), others when it is in very muddy conditions. Just like there are years when it is windy or it isn't very windy. Or years when it's sub-30 degrees at race time and years when it's over 40. Or years when it's raining, or even snowing, during the race and years when it's clear skies. These are all WEATHER CONDITIONS, and the only place you won't find them is in southern california where it's always going to be pretty dry and pretty warm. So, if you want the same conditions year after year, that's fine, head down to San Diego, but that doesn't make it "true cross country" just because the weather is consistent.
Whether you're racing at Footlocker or NXN, you still have to toe the line and run the same course as everyone else, first to the line is the winner. Period.
Yes, as I said, I prefer courses with a bit of variety rather than courses that are flat/fast grass tracks because it allows for a greater variety of strategy that can alter how the race is run. But that's just my own personal preference (and both national courses offer that).