The most important gear for meele is weapon.
Bow for Hunter.
Sounds like casters don't care about weapons.
True or False?
Now it seems caster staff has a +6000 spell power.
It is important now. When did that start?
What do you mean? Spellpower has always been important for casters. In previous expansions it was spell damage and healing power, then combined, but it's always been important.
A bow is a weapon. Aside from that, it started all the way back in vanilla. I think the first weapons with spell damage/healing where from MC.
Weapons have been the single most important piece of gear for just about everyone except tanks ever since.
It started with Cataclysm because you're right, weapons weren't nearly as important for casters as they were for melee and Hunters before then.
weapon upgrades are disproportional for classes.
For purely weapon damage classes(like 90% weapon damage skills, very few "ap only") a weapon is 2x better than entire attack power from all armor.
normal sha weapon = 4500 dps = 63,000 attack power.
a 489 warrior has like 35k attack power fully buffed and no procs not counting his weapon
Casters on the other hand should have like 14,000 spell power from intellect alone, weapon adds 7000 or so. not that huge of an upgrade.
same for ap-based classes like assassination rogues, huge portion of damage comes from only AP like poisons, bleeds, envenom/