I'm currently running gowen do to the fact you can make a ridiculously powerful deck with almost nothing where as my refess deck still lacks a several key cards needed to be successful even after 4 boxes of set 2 and who knows how much set 1. That said, I completely support Grain in doing this. Building card files or decks in any card game is and always has been about building the deck best suited to succeed in your current meta. If the current meta is gowen heavy, building specifically to counter Gowen makes perfect sense.
Lets look at it this way, lets say his deck could beat any other sphere but gowen most of the time previously, but almost always lost to gowen. Whats more he's running into gowen 3 times for every 5 he plays. That means he's averaging a 2 wins for every 3 losses. Now lets say with anti-gowen soul cards he's usually losing to non gowen since he has useless soul cards against them, but he's almost always beating gowen. Now on average he's winning 3 times for every 2 losses. Seems like a pretty good strategy to me, his win percentage went from 40% to 60%. And with those wins maybe he gets enough weekly gran/treasure battles to build a deck capable of beating gowen with out resorting to anti-gowen soul skills, so now he's no longer in trouble if the meta changes. I just don't see any real downside here for him.
The bunnies of Lavato have special abilities, like 'Action Skill: Make Carrot Disappear.'