The change to ethereal doesn't make him unplayable, as he pratically plays for his provisions on deploy, and still has huge point potential... But being so easy to remove, he'll probably only be viable with defender.
HOWEVER... Just because he won't be horrible, i still bet he will be avoided almost completely now. Because after a nerf, players dont judge a card by its state post-nerf, but by how big the nerf was, and Ethereal's nerf is HUGE, going from "carrying an entire faction" into " just acceptable".
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On the topic of Leshen/Force of Nature, it's definitely an improvement on the ability - it got better (proc thrive twice in a turn, points divided on more bodies so less risk), but it also became more boring, killed the possibility of MO hyperthin reveal meme deck.