I imagine that they probably haven't fully decided exactly what the weather effects and such will do, they didn't actually imagine they'd make the $1M goal.
While they may not know exactly what they will do and thing may change, since the game is still in development, I think they have a very good idea what and how it will work. It is a nightmare finding quotes in the kickstarter page, but they did say to come up with the goals they had a meeting to see what could be done and what could not and they put a priority on the goals. For them to be able to have a budget and know how much it would cost them to implement those goals, they have to have a good idea how it is going to work or you could not forecast the cost. I know when I am dealing with budgets as large as the budget for D:OS I know what these variables are and how the projections are going to work into the budget so I do not go over budget. While kickstarter was new for Larian, I give Swen a lot of credit for being able to run his company and doing so as well as he has. He is not inept at knowing what it would cost to make his game and he has a vision on how these things work. They did not pull a dollar amount of thin air. Imagine the pr nightmare it would be if they set a goal at a dollar amount and could not follow through because they had not thought about it before hand. Swen is too smart to allow something like that happen. Therefore, since they already had at least one meeting starting almost two months ago on these very things they have to have an idea, I want to know the idea. I am guessing I am not the only one.