I got into this game at the start of season 2. Seeing a large part of my collection become invalid for competitive play hurt. Quite a bit.
But I also thought this was coming. Not right now, and not in this way specifically, but some kind of rotation. It STILL hurt, and there's nothing anyone can say or do that remedies that. It's an emotional, irrational reaction. Not one stemming from reason.
However, the more I think about deck builds and the more games I play, the more the game surprises me. It feels fresh. And that, in the end, is what will keep me and others playing, and what will pull new players in.