Character development means nothing if the characters themselves are generic copies of previous FF characters. Take Cloud, slap a new back story on him and give him a smile by end game and bang - you got a new character with more develpment.
It's as easy as take whatever crap you got and dump it all into one weapon. All you really need to know is to use organic components first to boost the multiplier but that's as complicated as it gets.
FFX and FFXII required SPECIFIC ingredients which forced you to visit different locations to shop, steal or find the items you want. In FFXIII you just bulk buy the same two components.
Actually... no it isn't. FFXIII actively discourages the use of superior weapons because 5 star post battle rankings are nearly impossible when you use them. Also, your strength really isn't that important once you stagger something and reach a chain bonus that allows you to deal x 999% damage.
Everything in FFXIII has a cheap way to kill it. Ratkavija's giving you trouble - make yourself immune to magic. Need to kill adamantoises - spam death. Even the super boss vercingatorix is eaten away by poisen while you sit there and defend while he dies. No effort went into these bosses at all.
Yiazmat is a test of endurance and only becomes challenging after going below 5million HP where his physical attack gains no charge time and his multiple hit rating goes up stupidly high. But still, try and beat him without leaving to save. He has a number of tricks that can throw you off and if you're not paying attention you'll pay for it (Reflect on your party is nasty if you don't catch him do it) Still, not the toughest boss in XII in my opinion but effort wise, he's got alot more going on than any boss in XIII