By resource I mean Rage, Mana, Arcane Power, Spirit and Hatred/Discipline.
As we know Witch Doctor recently got scaling costs for their skills. Mana cost of skills start at cheap and increase as you level up. Maximum mana pool also becomes bigger as you level up, however the mana regeneration doesn't increase, giving Witch Doctors mana problems later on that need to be solved through equipment choices.
I searched the official forums, but couldn't find much information of resource scaling for other classes. There are passives and other abilities that increase both maximum resource caps and resource generation. Many skills also have one rune that reduces the casting cost of that skill. I've also seen some evidence of class-specific equipment giving extra resources on critical hits and flat increases to maximum amount you can have. Now all of this seems quite redundant if skills wouldn't have increasing costs as you level up. Does someone have info on this matter?
Stabsey's impression is spot on. Every class other than WD will function like rogues from WoW, their resource pool and passive regeneration rate (if any) stay basically the same throughout the game. Gear and skills choises will modify it somewhat, meaning that some builds will be able to spam a spender skill that would require way too long to recharge from other builds. Adds one extra layer of depth to designing an effective build!
The witch doctor does not have resource generating abilities, so he has a greater pool and a decent default regeneration to be able to adapt to different situations.
Resource management is a key element of the game you have to consider when making a build, no matter which class you play.