IMHO, I consider this good news. A once per year update tells me that they are trying to rush things. Rushing anything causes problems and also would keep Apple from implementing major features. Example: it would be hard to expect revolutionary changes in Tiger if they released the OS exactly one year after Panther.
That and I'm wondering if Panther bit them in the butt with the number of bugs that were found after release some quite critical. I'm hoping Apple shoots for Spring\Summer of '05 for the release of Tiger and then another revamp, Lynx?, in Fall of '06 after longhorn is released to bitchslap it into place with new features that longhorn won't have.