Unless i am doing it wrong, there seem to be about 2400 founder star names so far. (so much for "we are not expecting to get 1000 founders.")
Of course stardock will be adding star names of their own, my galciv2 star file has about 1500 star names in it. No doubt there will be some overlap but probably not to much.
So using these numbers and assuming all the star names are just thrown in one big list, in your average game you should get a little over 60% Player submitted star names.
Of course the number of founders is probably still going to go up but i doubt there will be a huge sales spike, and of courses stardock can add more star names of their own but even if they double the amount from galciv2, were still looking at about 40-50% player submitted star names.
It is also possible stardock will limit the percentage of player stars to a fixed amount, but should they?
Personally i think i would like to see mostly "realistic" star names, and while a lot of player names fit that, a lot of them do not. So i would probably say about 25% of player named stars would be a good number to keep the less star sounding names as a flavor thing at about 10-15%.
What do you think a good percentage of player star names would be?