Greetings...
You know you have to write a reply when you start arguing with your monitor...
I too am a world-builder. I think there is a guild of them on the 'net. I usually start with:
http://hiddenway.tripod.com/world/.
1) Why do you create your own setting?
But like others... it is an entertaining mental exercise for me.
2) Why do you use your own homebrew settings rather than using a published one?
It's easier to make it than to learn it. Call it lazy, call it creative, call it vanity. I'd rather pinch and steal good ideas from other compaigns, and put them into my own world than to use someone else's world and then have to shoe-horn my own ideas into it.
3) Am I still homebrewing if I'm borrowing elements from other settings?
Of course you are. But I would argue that your homebrewing the first time you change *ANYTHING*, and now you have something that isn't as stated in any book. Regardless if it's unrecognizable from the original model, or it's just a couple of minor tweaks. What you've created is now yours, and that's homebrewing.
4) If your homebrew setting is so vanilla that it's practically indistinguisable from hoardes of other such settings, then why bother creating it?
Entropy! Entropy!
-- It's a great mental exercise for me. Especially when I'm bored. Also, it's a lot of fun doing this mental exploration and finding things and creating things you didn't expect. One of the things I love about GMing, especially with creative players, is that they help shape your campaign world in ways you didn't expect. Making the process serindipitious and IMNSHO, more fun.
I think all world-builders would at some level say that ultimately they are more comfortable with their own world. Only because it makes more sense to them, or they would say that they know it better. Or it's too much trouble learning all the nooks and crannies of published setting. When I look at FR or DL, or even homebrewed worlds now, like it was mentioned before... there is always something there that bothers me, that I don't like. For me, it's a matter of logic. It doesn't seem logical. Or it seems too hokey, or whatever. I'll loose interest in it.
For me, I do the whole 'What If' thing too. But I center all my efforts on one world. I don't think of an aquatic world one day, and a firy inferno world the next. I think one world would be enough to have all these various environments and settings. *IF* I want to put them in there. -- I believe in leaving some things empty so you can fill in the details later. Let the players help shape the world with you. It's a lot more interesting that way.
On the other hand, it's cool if you are really hot for Greyhawke or bonzo for Blackmoor. But here's the thing. You could be the most devoted fan to a published setting. As soon as you start playing in that game. From Day One, that setting is now yours. You've changed it just by using it. Rather Heisenberg/Uncertainity-Principle eh?
http://en.wikipedia.org/wiki/Constructed_world
I rather like discussing the whole philosophy of world building. Make it detailed as possible, and try to anticipate what information your going to need? Or leave the world unexplored and not detailed, so that you can shape it with your follow gamers. Get into that whole top-down/bottom-up thing.
But the way I see it, everyone is going to have that creative dry spell, everyone is going to find something cool and interesting in some other setting, movie, book, whatever. Which is why I've tried to design my own campaign setting to factor that in. That I give players and GMs a world, that will hopefully let you plug in your favourite bits from other worlds/games/books/homebrews so that you will eventually be creating your own world.
I try to believe in the Eberron philosphy that 'if it had a place in D&D, it should have a place in my world...somewhere.' For example, for the longest time I've debated if I should remove paladins all together from my game world. They really are just a combination of clerics and fighters. I really don't like them, the whole concept of being a bastion of truth and justice yet also being godless doesn't sit right with me. Of course that leads me into Generic Classes or Gestalt Characters...which is fine... but then not all players want to do that. Tinker with the ideas, but try not to change the game so much that your players aren't going to be not comfortable with playing anymore.
But I see looking at other sources as sort of like creative world-building training wheels. We start people off with a published world. Sooner or later, someone says
"I don't like that... If I were the one writing this, I would have done...whatever..." -- That's why I tend to write a lot of world-building theory and discussions in with my GM notes... Not to mention, I want the GMs to get inside of my head and understand what I was thinking, and where I was going with all the stuff I create.
Oh, it's fine enough to give people a map, descriptions, from politics to racial makeup, religions, legends, attitudes and everything they could possibly want or need. But there are two problems with that. First is, you never want to do too much work, because if you do, you might feel that all that work is unappreciated. Also, there is that factor of 'why'...why is something there? If something doesn't seem right, logical... I want reading to be able to question those things. If you as a reader understand my purpose, then you can then understand my campaign world. That's something I thought a lot of published and homebrew worlds don't have, a perspective of where the creator is coming from. Not to mention, if I make a horrible mistake, and make something completely illogical, I want to know about it.
Most GMs fall somewhere in the middle between creating a world totally from scratch, and using a published campaign world. One who sort of picks and chooses the 'coolest' things from other sources.
I think the trick is to keep your creativity flowing. Read more, write more, watch more movies, watch more bad movies. Check out other people's worlds. Help someone build their world. -- I wonder if there is a forum where I can post my 'world vision' and have others pick it apart? Questions and answers...sounds morbidly fascinating.
My personal theory about world-building in regards to things being 'vanilla'... well, all I can say about that is...
The word "vanilla" has come to mean "bland, boring, commonplace". Pretty strange when you consider that this rare pod grows on an orchid that can only be pollinated one day a year. -- Well, all worlds suffer from an escalation of 'fantasy'. That you put something cool in, some new, some different. You end up having to top yourself next time you put something bigger, meaner, tougher. Soon enough you may end up with dragon-riders and floating castles. Or you make a concious effort to keep things simple.
Starting off a world as vanilla/generic as possible gives you lots of wiggle room so your not painting yourself into a corner, creatively. There is a certain amount of entropy to a game-world as well. The better you plan for this, the longer it's going to last. But really!? What is vanilla anyway? You have a demonic invasion. Hordes of monsters invading the lands of the good. Or, you have demonic merchants who are invading in their own clandestine and occult way. However way you may structure your game, it all boils down to monsters, heroes, adventure and fun. So, once you start looking at the unique details of one campaign world to another... nothing is ever really vanilla again. -- The secret here is not to get the cheap artificial vanilla. It has to be the real deal. It has to have lots of flavour and detail and richness.
Everybody likes a little something different in their published worlds. So, I say make sure that you have something for everyone. Yeah, someone might like a world that is dungeon-lite... someone else always wants dungeon-heavy. So, I say put it out there, if you dont want or like it, you can always ignore it, or create your own world. But I belive that creativity doesn't spontaeously form in a vaccuum. If you world is always on your mind, like mine is... some things are just going to creep in. Watching http://www.cbc.ca/parents/lunarJim.html has given me some ideas on faerie food.
When you create your own world, then it's as gritty, complex, strange... as you like it. Which of course only makes it that much more endearing. Not to mention, your offspring is always more cutier than others, aren't they? Only problem is it is a Herculean task, or perhaps I should say Atlasian task of documenting your world. It's a lot of work, and can be a bit despressing when players don't share the same interest or seem to appreciate the effort you've put into it.
Then there is the discussion about all the various campaign settings trying to be different. Having that cool need 'thing'. Well, not everyone is going to like everything in this brave new world. Regardless if it's published or not.
The problem I always had with published game worlds is that you can always have that rule-laywer who knows more about the setting than you do, and you have to resort to the cavaté "Well, this is my world now." -- That has always left a bad taste in my mouth. I don't want to lay the smack-down on players, especially when they are just trying to help. -- I know I've been guilty of it too. Frustrated my DMs to no end, until I realized I just has to preface my questions and arguements with the reasoning I have. *Well, here we have the faerie kingdoms, and you've called them Avalon, are they actually other-worldly, or are they actually a physical place? Because everything I've been lead to believe in regards to Avalon is...*
Not to mention, there is always that problem when the players reading all the GM information making the whole idea moot now. But who can blame them? All the good information is in the GM notes anyway. This way, there are always mysteries to solve and new exciting things to discover, because they haven't already read them in a book/supplement.