While holding a shield large cluster jewels should grant increased damage with attack skill

The difference being that the increase apply to damage over time from attack skills, like damaging ailments. Should be the same for dual wielding while you're at it.

Why is it different from weapon specific cluster jewel? Especially since most notable granted by the shield cluster jewel have increased damage with attack skills.

I find it infuriating to create a build when large parts of the passive tree only affect hits or only affect dots for what appears to be ABSOLUTELY NO REASON.

I'm sorry, this makes me angry.