My testing partner Seiken already redid the stat cap testing for melees. He prefers to post his results and methods directly into the official forums. Thread here:
http://forum.square-enix.com/ffxiv/t...l=1#post607045
New stat caps according to his post-1.21 testing are...
PGL/MNK: 348STR/305-310INT
LNC/DRG: 348STR/305-310PIE
MAR/WAR: 348STR/305-310VIT
ARC/BRD: 330PIE/295-300DEX
GLA/PLD was not tested. Tested using Ifrit's weapons. If you use another weapon with lower base damage, these caps will DECREASE. The base damage alters the caps. These are the caps for weapon skills. He assumed that all WSs would have the same cap after testing 2 WAR WSs and found they had the same cap. Auto-attack stats will cap earlier, but he figured people would only care about the WS caps so he focused on posting that. If you want the auto-attack / light shot caps I can dig up the excel file he gave me.
It is ALWAYS to your advantage to cap the stat before focusing on ATK. Also remember that if STR is your modifier (say on MNK), you get 2-fold benefit for +1STR (1 for the mod and 1 for the fact STR is always 0.67 ATK). After you hit your 348 STR cap, you'll only get the 2:3 ratio bonus.
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There is a MATK cap. There is also actually an ATK cap. They are both essentially unreachable for anything you would ever care about killing. The only spell that is ever in danger of having a capped MATK on R45+ mobs is Thundara (combo) because the Thundara combo bonus gives you an additional +700 MATK, and I've never seen it cap on an R45+ mob. INT does not cap like melee stats. Unlike the melee formulas, INT and MATK are DEPENDENT variables (similar to XI's magic damage formula). The difficulty of testing with dependent variables is 1 reason why we have not posted MATK testing but nearly all the melee stuff is out (besides this, Seiken is a more rigorous tester than me). This means that the effect/bonus generated by 1 is dependent on what the other currently is. For all spells other than Thundara on combo, MATK is better than INT when talking point for point. For thundara on combo, INT beats MATK easily due to the fact the game is giving you +700MATK for doing it in combo. This means if you are fighting something where you spam thunder combo (e.g. Chimera or Ifrit), stack INT once you have sufficient MACC. For something where you would spam fire nukes (normal stuff, Miser's Mistress), stack MATK first. Just remember that 4 INT = 1 MATK as well so don't disregard INT.