The biggest problem I found with cloud giant vuln's is you get used to eating certain amounts of damage from physical, so when people start hitting you with wrath weapons it is a big difference. I would say cloud giants probably have more advantages than disadvantages as long as you are not going Nexus and expecting to face berserkers nonstop. Berserkers are likely to find a wrath weapon (they are incredibly common) and a few deathblows later you will be toast.