The Sphere Grid has been recycled too many times in the FF series (It also appeared under different names in FFXII and XIII), as it was a broken system to begin with - it's utterly linear and doesn't actually give customization at all (the only 'freedom' the player has in customizing their character is how quickly you proceed through it). And the trouble with your 'Twelve' based system is players will inevitably find the best one to use with a certain class, and thus favoritism will occur - what SE are actually trying to avoid with FFXIV's system (it's the reason why we don't have elemental spells for one thing).

FFXI merits on the other hand, I can definitely see being added in one form or another. The Merit System was added into FFXI to compensate having the level cap frozen at 75 for so long, thus allowing players to customize their character beyond the level cap. But given the fact FFXIV uses item level to break the current level cap, I don't see Merits or something like them being added any time soon sadly.