There is for sure a case to be made by looking at the aggregate win rate of all the matches for each God. But that doesn't necessarily indicate that the decks from that particular God are not competitive. It could mean that players are just not able to make the most of the cards. It is also possible that players in the lower ranks are not using the more expensive cards that are necessary to make the decks competitive. On the other hand, Guild Deception is a notably cheap and effective deck, although pointed by many as a high skill deck that needs good understanding of the matchups and strategies to be successful.

Looking at Light (before the new expansion) and how the individual decks performed, I think there was a power issue. Light decks in the current meta are generally simple to pilot, but yet they under-perform against many of the other meta decks - and this results in an overall lower win rate.

But the point I was trying to make initially with the screenshots is that this is not the case for Deception. For sure players lose a lot of games, but the reason for that is not the lack of solid, competitive decks.