Hey Gamesta, just been reading the OP and noticed all the weather change tracks will be started in sunny conditions, this means that we could do all the weather change races without any change in weather.
I'd maybe suggest starting one or maybe two races in wet conditions. By not setting the weather to fixed, the race could still become dry meaning we get an exciting period were someone has to blink first and come in for slicks.
Just an idea! Maybe i'm bias because I like the rain!!