I will say this, the discounts are decided by the developers/publishers, so they can choose how to discount it. But there is discussion of the devalue of games and to be wise of your product, but there's a lot of different viewpoints on this topic.
However, my hope is to find some other way to make sales 'fun' for the more hardcore fans. Valve kind of experimented last Winter Sale with the Gem Raffle system and earlier this year with the Clicker minigame thing. Both are not tied into daily deals, are were a bit of fun (I liked the raffle more than the Clicker game, personally), so if they can find other avenues like that, I think most wouldn't mind as much. While I know a sale is a sale and it doesn't need to be 'fun', I think that was one attractive aspect to Valve's storefront, even though the data does show that the sales do a lot better with their new method.