The server has now added tiered rewards for completing your Pokedex. Check your quest book and look for the Pokedex Milestone Rewards to see what you can get at each tier. Note that due to technical limitations, you will need to get your Pokedex appraised occasionally by Rokku in order to receive your rewards. You don't need to get it appraised at each tier; just come see me once you've stockpiled a few.
As you can see, there is an extensive variety of rewards that you will receive for progressing the Pokedex. Note that the Shiny Charm gets given out at 50% dex completion! Try your hand at exploring the world whenever you have some time.