On Conflict in Gamedesign

I'm currently working on a larger gaming project, pen and paper roleplaying, to be precise.
I'm trying to work on a setting for a game and since I'm not exactly a veteran game designer, I'll probably make all kinds of mistakes on the way. Anyway, I'll try to voice some of my thoughts on conflict and cultures here, in the hopes that writing about it might help me clear my mind and get things straight
(Hey, it's called random ramblings for a reason!).

So, the biggest problem I currently have with the game setting is the lack of obvious conflict.
I think that this is a problem.Of course, there are all sorts of monsters out there in the wilderness to be slain and relieved of their treasure, but I have the feeling this might not be enough of a hook to hang compelling adventures, let alone campaigns on for long.
So I am looking at different ways to include better adventure reasons. And the prime reason for going out and having adventures, which tend to be somewhat unpleasant, is conflict between different groups and cultures.
So I think the setting needs some kind of conflict but I'm not sure how to go about it.
So far, I have identified three different kinds of conflict: intercultural, intracultural and external conflict.
Let me explain what I mean by these three names in some detail.
Intercultural conflict is conflict between two (or more) different cultures (in a fantasy game this usually means races like Dwarves, Elves etc.). It most often takes the form of war, one culture invading the other, that kind of thing.
It is pretty straight forward and I only need cultures that are so different in outlook that it is only a matter of time until they clash.

Intracultural conflict is about struggles within one society. Revolutions, religious arguments and so forth are the most common appearances of this kind of conflict.

External conflict is something very metaplotish in nature, an external threat to the whole world and all cultures or a world-defining conflict like tech vs. magic.

The next thing to keep in mind is scale, meaning the relation in which each conflict standts to all other conflicts and the lifes of the potential player characters.
This is the fiddly bit, since it defines the atmosphere of the entire gaming world.
The question this all raises is to metaplot or not to metaplot, something I'll have to work on soon.
For the moment I'll try to get a moderate number of small scale intracultural conflicts, a few intercultural conflicts of medium scale and one large external conflict to put the whole setting into a perspective that makes it easy to understand.
I'll probably go with an external threat, firstly because I like cosmic horror and such things and secondly because I just can't come up with an interesting alternative to tech vs. magic which has been done to death already.
This large conflict will be very much in the background, good material for an epic campaign, whereas the small and medium conflicts will be more apropriate for adventures and shorter campaigns.
Now if only I could come up with enough of these without making the whole setting too complicated.