Can we let shields stack?

[Sylvain]

You can't make shields stack (especially aoe) for a very and simple good reason, it highly raise effective hp. One of the difficulty of new savage content is to survive burst (tank or aoe or transition). This is why worldfirst often meld vitality, because it raises their hp by the tiny bit needed to survive better
By allowing sheild to stack you can effectively negate many mechanics such as tank buster.
Same goes for the weakness debuff, they basically are a death sentence if you don't have enough gear to mitigate, allow shields to stack and weakness debuff would be much less of a threat.

The comparison between Hot is bad because hot don't prevent death.
Let say you have 50k hp, you could have 7 WHM hots, if the boss does 50 001 dmg in one hit. You die
If you have a shield absorbing 2 dmg, you survive.

Divine is a special case because it's a single target skill that has a cd. If I'm right TBN also stack too.

If you think double hots is so great, just do something like Shinryu with min ilv with WHM in diurnal stance, tell me how it goes and how open those stacking hots were (small hint, without perfect use of tank aoe mitigation and AST bubble, all your squishes will die)