You could make that same argument for any potentially broken item in the game. "Well its on you to figure out how to beat it even though it is overpowered". Sometimes things are overpowered and need fixing. When that is the case it is not up to the player to figure it out. It is broken and needs to be fixed. Someone wearing a tier 4 robe (again non-artifact) and taking no damage for 3 seconds against a tier 8 weapon, means something is wrong. I would be okay with changing the duration per level with the 8.3 having the 3 seconds and it gets shorter in time as you scale down the item power, but something is not right here at the moment. So argue if you will, it just proves you are one of the people who are using it and don't want to have to adjust your game.It's your fault if you can't figure out how to out play against the cleric robe user to beat them, not the fault of the cleric robe.
One of ur main arguments was that the cleric robe shield lasts for 3 seconds but come on guy it's only 3 seconds just walk the other way for a bit or don't get baited using one of ur main weapons abilities on it idk
Don't forget capes are purge-able, this means if you're using martlock cape for example against a black hands that he may simply purge the capes ability. Also keeper cape is purgeable etc.