I don't have any major issues with it

Death door Unique skill ... I would have to say ... no at this point.
The way you added it isn't exactly that of a unique skill.
Both the toggles will have to be of high level mastery, and Soul Harvest will probably go down after a duration. (Example, you capture 50 souls, but you leave battle for 5 minutes, every minute the soul count goes down so the chance to get higher drops goes down) Otherwise you could stack it to 1000000000000, and have ridiculous drop rates

Most of the Skills seem to be of a "Medium" skill level at least, so I doubt you will get to use many of them yet. I'd say Cresent Moon and Shockwave.
Last Word .... I need to think on that a bit more
I'll try to design a couple more that are more suitable for the lower end to use.