These are just some suggestions to enhance the Darkness domain as I notice it feels like its lacking or missing emphasis on Darkness.
First - Summons from the Darkness domain tend to have the shadow descriptor much like the Shadow Conjuration spell. I wonder if there was a script to add this to all summons of this domain to better enhance and stylize it.
Second - For Clerics there are access to Light spells. However with the Darkness domain you would figure there was access to more Darkness/Shadow spells. Perhaps adding some of the new Shadow Spells to this domain in place of light spells. For Example the domain recieves Shadow Conjuration, Slashing Darkness, Darkness, and Daming Darkness. But, you would believe it would alao aquire Cone of Dimness in place of Frost Breath, Shadoe Bind instead of Shackle, Shadow Mantle, and Shade instead of Radiant Assault.
These are just suggestions. I been reading up on Clerics who use the shadow domain and thought this may enhance or better define the role of those who use the Shadow Weave or Darkness profile in other worlds. Food for thought.