Case in point: Vaarsuvius. So many years and no one has the slightest idea what their gender is. This ambiguity was used for quite a few jokes, but did this affect the plot in any particular way? Nope. To be honest, the only plot-relevant gender so far in OotS was Durkon's due to him having a son with Hilgya and only learning about it way later.
So I would say the sane way of looking at it in any fiction would be the following: try assuming different genders of a given character and think if that changes anything. If it does not, there is no reason to care about such details.
edit: awful grammar errors.