Yes, as the people here said, the magic of FPSC comes with time and usage, it means, patience and perseverance.
You must need as is said, at least 1 year of hard working on FPSC, to be able to use all the features and power it has to offer.
I think you must first learn the basics of FPSC, the basic usage of the map editor, waypoints, entities, segments (just following the manual). Then you go to learn how to create your own entities, importing custom models and animations in FPSC.
But when you come to this point, is very good that you have at least a basic knowledge of 3D modeling and animation, to be able to have your unique game assets.
So after those basic steps, which you can accomplish them just by following the manual that comes with FPSC, you can go to learn FPI Scripting. When i first began to study it, i really was a little "scared" about it, i could never understand well the "state" thing, but after a time, you get it, it`s not that hard.
A good, i mean, excellent resource for learning FPI Scripting is the Official Community Guide (the 2 editions).
So whenever you learn well scripting, you can move on to another "advanced" steps, like creating you own weapons, and then you can also learn to use the Segments Editor (again it`s very good that you have a well understanding of 3d modelling).
I think if someone wants to really learn FPSC to create a very cool game on it is to prepare a kind of "study program" for himself. I have done it.
In example, i am creating a Goldeneye 007 Fan Game, based on the Nintendo Wii Version, so i played a lot this game on the emulator, i have done a kind of brainstorming, so i have maked up a list of effects and features this game has, as a way to me organize myself to know what features i can reproduce on FPSC.
The basic system of this game, the Mission Objectives, the level of difficulties, different number of achievements to accomplish according to the level of difficulty, i could reproduce this using the Model Pack 54 (Scary Thinker), off course by changing it`s scripts a lot.
And so on.
So off course, it is possible to create a very professional FPSC game.
Cheers,
007.
Goldenye 007 N64