No... 80% did not suffer from not having slow AND movement speed increase same time.
That was virtually only issue for Paladin and Priest.
For "ret" paladin that was a killer because they were melee and got kited to death, literally and what's worse they could not even do any sort of real attrition fighting because their piddly blue bar was enough for couple of heals after which said paladin was a sitting duck. Almost every class aside from Priests could chain CC and kite paladin to death and Priests could simply burn away his piddly mana bar in couple of casts and then dispel all buffs at which point it was RIP anyway.
And you say they were "beastly in World PvP"... are you real? It was auto loss vs Priest, Mage, Warlock, Hunter and Rogue in World PvP because 3 of them could reset fight 500 times until paladin runs oom and has no cds, while 4th simply dispelled and mana burned paladin to death within a fear and 5th simply could kite said paladin to Orgrimmar and back forever.