The "This isn't BG3 it's DOS3" crowd would probably explode out of anger if this happened.
Personally I think this is unlikely to happen. With the 5e rules needing to be changed so much already to fit Larians vision, entirely homebrewed subclasses might break the deal they got with WotC. Let the modders handle this one.
Yup XD This wouldn't end well.
Jokes aside, there is really no need for it though. D&D has a loooooot of content when it comes to classes, sub classes , spells etc. So there will be a lot to play around with. ^^
Metamorph is arguably a druid.