About even out the holidays with new traits, there's more holidays during the winter half of the year than there is during the summer half of the year. The special limited edition cats are often based off of the holidays in RL. I think that could be why it's hard to even out the trait-releases. (Though I wouldn't mind a midsummer-holiday event of new special kittans!
They could sell lil maypoles as scratching posts for the cats to climb! :3). And during the summer a lot of people go off on holiday and if something gets released while they are off sunbathing we would be getting threads complaining about KC not being considerate of the people that go off on holiday on the summers and other people getting a headstart cuz they didn't go off on holiday and so on. Sometimes there is no pleasing everyone, I'm happy with how the releases work currently because I can spend my summers saving up, perhaps even go out and buy an icecream and sit in the sun for a day, getting ready for the winter half of the year and the excitement of new cats and new collectibles.