What class or classes have been consistently good and have not really ever been bad throughout the entire game? Vanilla - now.
For DPS I would say warlock, mage or rogue
What class or classes have been consistently good and have not really ever been bad throughout the entire game? Vanilla - now.
For DPS I would say warlock, mage or rogue
Well atm Warlock is overtuned and will likely be getting nerfed in 8.2 to bring them back into line with the rest (see the logs). But any pure DPS class will usually do OK over the years due to having multiple DPS specs. There are exceptions however. Arms Warrior atm is apparently trash dps, hence why all warriors are fury atm. But that just proves my point. Any class with more than one DPS spec will usually be OK. Which makes me most sorry for the DH’s. They have one uber DPS spec and a meh tank spec. Unfortunately due to the lack of a 3rd spec (like DK’s), they are extremely vulnerable to getting pwnt by Blizz at some point. I don’t know why Blizz didn’t give DH’s the DK treatment.
Human Male Paladin. What else?
The entire class or by spec? Because Demonology was bad when they decided to gut Metamorphosis and left it crippled for a very long time.
Warlock for most consistently strong class when considering both pve and pvp.
The entire class in general, regardless of spec.
Lock imo. Always one or two specs up top
Not always the case though. Warlocks were pretty poor in Vanilla.
Rogue has always been there.
What about, like, DKs?
Dk is crap rn. Cept bdk
EDIT
you take it back!
My opinion only, I’d say DK, rogue and mage once you get past level 50. Idk much about the other classes.
I haven’t played since vanilla though, only since 2011.
I main a FDK
I shall not 
Warlock. Literally always good.
Reeeetardins(Iplayone):c
It’s probably lock.
A lot of people say rogue, but rogues have had weird histories. A lot of times what happens is they start the expansion strong, people complain and Blizzard nerfs them, then come last patch they have to buff them and then they’re OP again.
Where as warlock are probably the most consistently good.
In terms of high raid viability it would be all the pure classes as they almost always had a spec that is top tier. Mage, Lock, Rogue, Hunter.
Warlock, mage, warrior, rogue. Always on top honorable mention to shadow priest.
Dh is a trash master ST is meh.
Warlocks hands down have always been on top of the DPS food chain. If you run into one, it definitely feels like you’re fighting five guys all at once. Mages have also been rather painfully annoying as well especially if you’re a melee class.
My main is a Druid, one of the specs is always good but it’s usually never too good so we usually fly under the radar lol