I don't think it's anything to do with colour. William's parents are a very laid back orange roan dog and a very busy and fizzy blue roan bitch. I don't see all of the litter now, but of those I've seen since they were small puppies there's -
my William - orange roan boy, very laid back, very confident.
Orange roan girl - very busy, just like her blue roan mum.
Orange roan boy - a bit of a barker and excitable (although, to be fair, I haven't seen him since he was about 9 moths old)
Blue roan boy - very laid back, very confident.