What determines the strength of a damage shield?

Seraphayel

The title says it all.

I know some shields scale of max health, some scale of Max Magicka. But which factors (buffs/debuffs) apply to shields as well?

Does (Major/Minor) Mending increase shield strength?

Do Shields crit now or still not a thing?

Is there a comprehensive list what determines the strength of the shield skill?

Mintaka5

Shields are capped at percentage of max health.

Dracane

The strenght of a shield is easily explained.
Let us take dampen magicka as an example. It caps at 50% of your health, so that is the strongest it can be under any circumstances. When you have 20k health, your shield can never be stronger than 10k, no matter what you try,

Its actual strenght is determined exclusively by your maximum magicka pool. No other buffs apply to this. Shield can not crit, are not affected by mending or anything else. You can try to increase their strenght with the Bastion passive, which usually will not have any impact. Because in comparison to 50% of our health, everyone's max magicka is already high enough to fill that low limit, resulting in Bastion having no further impact.

Seraphayel

With the UESP Skill Browser you can see which shield is affected by which attribute; this is very helpful.

Unfortunately the DK skill "Obsidian Shield" has a Health modifier which makes sense for the non-healer version. It's a bit of a shame that Igneous Shield (the healer morph) isn't scaling with Magicka but that might be too much. All of the "healer" shields scaling off of Magicka except the DK class shield is still a bit weird.