  In this Letter we investigate the basic assumptions of the decaying dark
matter (DDM) theory in the light of recent advances in observational and
theoretical cosmology and physics, i.e. detection of massive astrophysical
compact halo objects (MACHOs) and Super-Kamiokande results. Specifically, the
consequences pertaining to the shape of the Milky Way galaxy dark halo are
discussed. We find that, by taking into account the values of the main
constituent of the mass in DDM theory, massive neutrino, with the mass of 30
eV, and lifetime $\sim 10^{23}$ s, the initially proposed value of extreme halo
flattening $q\sim 0.2$ is no longer necessary, and that one can easily
accommodate a much larger value of $q\sim 0.6$, that is in accord with all
available observational data.
