For some perhaps. The key for me - if it was going to be a science fiction explanation, the explanation needed to explain how the uneven seasons work. Unless the how then is central to one of the plots, then it doesn't really matter, and the uneven seasons are interesting background that would only need explaining if the audience required "proof" that it has a science fiction explanation.
However, with it being a magical or supernatural explanation, the how can be thrown out the window ("A Wizard Did It"), but then we get a much more interesting question of "why?" And, in my opinion, particularly in an epic series such as this, all why questions must be answered for a satisfactory ending.