First off, let me try and make myself clear. Give the ability to thumbs up or thumbs down decks you beat in the arena, but regardless of what you do, their rank and rating loss is the same. The only thing that happens if you thumbs up a deck you beat, is that they gain a small
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reward for being creative. All too often you meet a super awesome deck and would love to thumbs it up, but you beat it. If everyone thumbs down boring ghostmares that beat you, I think people should also have the option to thumbs up decks that they win against but are really creative or nice.
Pros: Would help inspire more creativity in decks and make people build decks that aren't just purely made to win with boring tactics
Cons: May lessen creativity since some people will just make farms/bad decks for the compensatory reward