Considering the generally slow time-frames of most campaigns, I think the previous versions year and a day punishment equated to a total loss of a class ability, and in my experience, it just meant that the wizard/sorcerer who had a familiar, generally tried his best to just keep said familiar hidden on himself. I like the current incarnation better because it is more in line with the loss/use of an encounter power that was gained from a feat (like, for instance, the drow feat that lets them use both cloud of darkness AND darkfire, once per encounter).
