That being said, I like the build idea. A lot actually, seems quite a bit overpowered, but could be tweaked through play trials.
In regards to all the concern with "removing items" what i mean by that is keeping the artwork but renaming them to fit their new role as an item. Blizzard does this all the time in their patch notes, I'm unsure as to why so many were confused by this phrasing but oh well.
Yes, I get what you intend, but you are talking about items that already serve a function for other classes, so removing that function from the class would not be wise. So mainly referring to Corruption on my end.
Not sure if there is a shoulder in the game without a function at all. I think they could rework the "items do not receive durability reduction" shoulder without any true repercussions.
Pretty much what Demon said here, I know it's just an idea and all but if Blizzard is going to take the time to develop a new set it's going to have unique artwork. No sense in removing existing items just to use their art assets.
I don't think they should make a new set revolving around hydras just yet. If a new expansion comes down the road then it might be a good idea to introduce a new set for each class. That being said I do feel hydra is a little overlooked and would be cool to see it given a second look. Currently all of the sets have a signature spell they are tied into. Tal Rasha has meteors, Delsere has Slow Time, Vyr has Archon. Then there is firebird, it's niche is supposed to be the staple "fire mage" but never seems to be much more than a starter set since it's inception, it's hardly used which kinda sucks since I personally like the artwork on it more than the other sets. The chestpiece especially. Since all other wizard sets have a signature spell tie in it would be nice to see firebirds go that way and hydra seems the most likely spell to do it with.