Rookie Tank Questions

[Absurdity]

You'll hear often that GNB DPS is the best, but really, all the tanks have very similar DPS. It's like calling GNB the tallest toddler.

I think when people talk about GNB dps being the best it is for two reasons, it naturally aligns with raid buffs since it's big burst is every 60 seconds, unlike WAR and DRK, and it simply feels satisfying to execute due to the high apm and a bit of setup required, instead of just pressing 1 oGCD and spamming the same skill 5 times.
If we simply look at their personal dps then all the tanks are indeed extremely close to each other.