Thinking about it and the FF series hasn't been so bad for me.
In FFVI I didn't like using Mog in my party because I though he looked stupid (now I'm going to get hated on). As such I never got to use dance as a move set
In FFIX I dislike Quina with a passion and would like to limit her screen time as much as possible. Because of this I never get to play with Blue Magic in FFIX. Ditto for Steiner, so no magic sword.
In FFXIII I don't particularly care for Hope, I would much rather have another character in my party. His abilities, however, are indispensable to my play style.
---------------------
Regarding FFXIII:
In that game each character only has access to 3/6 classes for the first half of the game, and even when the other 3 are available they blow in comparison. The first tier of a class costs ~100-120 (I think) CP per 'sphere', whereas for one of the characters secondary classes it is 3000-6000 CP. By the time you get to Tier 4 it is 12000-24000 CP per sphere, and you are only getting ~+6-10 to a stat. If you were to use the pre-post game last level it would cost 12000-20000 CP for +20-40 in the same stats. So spending CP into classes that your character isn't default in is only worth 1/4 as much as if you had just stuck to the default.
Hope it made sense. Bottom line is you can spend any points in any class, but anything other than the 3 innate to the character is a huge rip of and inefficient use of experience.