Protohiro1, if you ever look at this, composite NTSC has trouble representing colors (relative to PAL), not because of a reduced color gamut, but because of the compression of the Q component of YIQ colorspace. Q is only allotted ~600KHz, where as I receives ~1.3MHz.
 
Not that it makes a difference, but I thought you might want to know. They probably skipped that one in film school and just said that composite NTSC sucks.