This video (and the text script in the description) is very helpful for stat caps.

http://www.youtube.com/watch?v=Moa08Y4i8uc

I agree that the system could be more transparent, but there IS a method to the madness. It's just that, like several other aspects of this game, it demands that you pay close attention to the rules.

I understand that people hate the materia system. While it could certainly use some improvement I think a lot of it has to do with not being familiar with it. I don't know how many times I've answered a shout for a "quick relic meld" only to stand in awkward silence while someone learns the basics of the entire materia system in front of me.