what will be the main stat for Rogue/Ninja?

[Exstal]

That's the basic argument I'm going with.

All loot has an equal chance to drop, regardless of how many classes can/should use it. As such, the

WAR: competes with PLD
PLD: competes with WAR
SMN: competes with BLM
BLM: competes with SMN
WHM: competes with SCH
SCH: competes with WHM
BRD: competes with no one
MNK: competes with no one for armor, competes with DRG for jewelry
DRG: competes with no one for armor, competes with MNK for jewelry

I think they may make it Monk armour, Dex accessories but that seems silly. On top of the fact that the Gun class is probably full on Dex so it's a hard guess to make.

Let's not forget those offtank builds.

Tanks can't roll <NEED> on STR accessories so that isn't a factor in the loot pooling.