It's not. Shake it Off is based on each individual player's health, not the WAR's. Divine Veil is based off the PLD's health. A 10% shield from a PLD (~12k) is going to be better than Shake it Off on a DRG wih 85k HP until you consume 2 cooldowns, and on a caster you need 3 cooldowns to beat Divine Veil. Plus you're completely ignoring PLD's second raidwide mitigation skill. GNB's and DRK's raidwide mitigation skills also have the difference of being % mitigation instead of a shield which will make them good for multiple hits in a short time.
Heart of Stone and Sheltron both last longer than Raw Intuition. Sheltron already matches RI's 20% mitigation and it will start scaling up as soon as we get tome gear while RI won't change. GNB also has more mitigation uptime with Camouflage's 10s extra duration over Thrill/Dark Mind.
That's definitely not something WAR has in this expansion. If you want versatile, look at PLD. It had the best tank skillset in Stormblood and it got even better in Shadowbringers.