I vote for 'when it is done', which should be October/November if Larian's projected estimates and budgets (from when they began the kickstarter) remain reasonably accurate. The amount of work to be done puts a lower limit on the release date, while the amount of money available gives an upper limit. If there ends up looking like there would be a large gap between the two, I think Larian would be more inclined to add more detail and polish than release early, but since all the stretch goals were met, that isn't likely to be an issue.