It sounds like they're mixing in aspects of FF9 (learn abilities through weapons) and some FF7 (materia for spell casting). Now as far as increasing character stats such as STR, DEX, VIT, MND, INT, CHR, my guess is that will come from wearing different styles of armor.
Now as for the "level" of the armor....I'm thinking that they're going to do it like..."in order to be able to equip this piece of body armor, you must have at least 15 STR and 10 VIT, and will have a max of 20 STR and 15 VIT that you can attain by wearing that armor. Once those caps are reached, you're due for some new armor.
That's my wild guess, anyhow....
Linkshell: LordOfTheBeasts (Pet LS/Social) and Heroes (Endgame)
Jobs: 75 BST, 75 THF, 75 BLM, 75 SAM, 75 DRK, 75 PUP, 75 SMN, 72 SCH, 69 BRD, 67 PLD, 66 RNG, 66 WAR, 63 RDM, 61 BLU, 57 DRG, 56 NIN, 54 MNK, 45 WHM, 32 COR (Jobs updated as of 8-28-09)
Leathercraft/Clothcraft Mule "Andersoncooper"
90.1 Leathercraft (Tanner's Gloves and Tanner's Apron: O)