Your GNB vs DRK comparisons you have a couple things wrong with IMO.

As a person who mains DRK and GNB saying TBN isnt as good as heart of stone what? TBN is not only a damage shield but also adds in a bonus edge of shadow. You also left out Shadow wall and delerium for DRK.

I love both of these jobs but GNB is a much better off tank hands down. DRK is more main tank.

As of now though we don't know what's meta. Or how hard some tank busters are going to hit. So PLD or DRK might be the better main tanks the a GNB because on GNB I definatly notice a diference on tank busters vs DRK.

Oh and as for bolide vs living dead..... bolide is what 8 seconds? Server ticks can kill you because it dumps hp to 1 before invuln kicks in. Where are LD is a 10 second window where if within that 10 seconds you drop below 1 hp you then gain 10 seconds of not dying. Down side after those 10 seconds if not cured to full you die.