I just read a great post about the subject, and felt let chiming in, albeit briefly. This is not a response or comment to the original post, but some reflections inspired by it. It is also a little rant-y, so reader beware.
The problem with maximalist settings, in my view, is an excess of boring stuff. I admit I loved detail when I was younger - it made the worlds feel real. Nowadays, I just don't have the time for that. I literally have more free RPGs in my HD than I can read in the next 10 years, not to mention the hundreds I payed for.
What is boring? Once again, Joseph Manola has successfully explained it: it is the predictable ("exactly what you would expect") and the irrelevant ("the headman of this village is tall and old and cheerful").
Now, this isn't a problem with campaign setting and modules only, but it affects monster manuals, player books and whole rules systems (it might even be a problem with a sizable part of modern literature, but I won't go into that here).
Take the three monster manuals I'm reading right now: Teratic Tome, Fire on the Velvet Horizon and Volo's Guide. While the first two aim to give you the awesome in every page (even at the risk of missing the mark), Volo's alternates freely between being awesome/useful (the new monsters and races, for example) and boring me to tears. For example, Gnolls are evil because their god is evil. Giants are artists, warriors or gluttons depending on their gods. and the hierarchy between goblins, hobgoblins and bugbears are determined by each one's gods. When I got to the "Orcs: the Godsworn" section, I put the book away and haven't pick it up since.
Or consider the infinite number of retroclones/neoclones: I really like reading this stuff, but why do I have to read 80-pages of d20 copypasta before I get to that one cool idea that makes your retro-clone different from the rest? Give me the awesome already!
For me, a 20-page PDF is ten times more useful than a 200-page PDF if 90% of it is filled with the obvious, and 50 flexible spells are better than 500 spells I won't read. 10 monsters I've never heard of? I'll take that over 50 orcs any day of the week. Please do not describe what a Minotaur (or - God forbid! - a human) looks like. I already know!
Sure, there is room for stuff such as Low Fantasy Gaming, which puts a S&S twist on the familiar stuff it presents, or thematic retro-clones like Seven Voyages of Zylarthen, but unless your work is very unique, we probably don't need another retro-clone by this point.
I am aware that many people think RPGs are meant to be referenced, not read. There is a place for this stuff, too; but honestly, if your game requires me to open it upo multiple times during play, I'm probably not te target audience. Give me something cool to read, and the chances I use it rise exponentially.
This is why I like Titan, by the way. This might be nostalgia talking, but everything seemed to be focused on adventure and fun, and it frequently departed from the obvious. Orcs are evil, which might sound dated, but not because they worship evil gods. In fact...
As you encounter servants of some of the gods of Good on
your travels, you may begin to wonder why so many 'evil'
races worship them! Surely, you would say, foul creatures
like Orcs would not wish to worship a god like Galana (who
they know as the Lady of Corn and pray to for good harvests
in the few areas where they still bother to grow crops), and
in return Galana would not bestow her favours upon servants
of Evil and Chaos, even if they were also farmers? This is part
of the very nature of Goodness, it seems: the powers of Good
are such that they can forgive the creatures of Evil enough to
grant them their blessing when they need it.
Creatures such as the Life-Stealers, who worship Sukh, are
considered servants of Evil because they live by violence and
killing, which they seem to do in the name of their god. In
such matters, religion breaks down a little, it must be said,
and priests have argued with one another for centuries over
such points. In the case of Sukh, it is generally agreed that
Life-Stealers kill their victims only because that is the way
they are. Certainly, no one seems to argue much when
humans slaughter Orcs or Goblins, though most servants of
Good would agree that killing is – at least in principle –always
an act of Evil.
When I was a teenager, I wrote a "kitchen sink" setting with all the stuff I wanted to have in a D&Dish world. I took a completionist approach to it: everything had to make sense and have a detailed explanation, down to the percentage of people that spoke a given language in a given country. I eventually gave up on it because this kind of detail became uninteresting even to my players.
Recently, I tried rewriting it, with two rules in mind: everything must be either awesome or short. Which, in my opinion, is the cure for predictable and irrelevant. Yes, you need some irrelevant stuff to make sense of a setting ("the king is called Damocles the Third..."), but if you make it short you leave the spotlight to the cool stuff - and save everyone's time.
There is a lot more to be said on the matter, but making this too long would miss the point, right? So, rant over. See you soon!