There are a few things to consider with how Larian does their kickstarter.
1.) There will "most likely" be a tier where the game will be much cheaper then when finally released...though it will be just a digital copy download off GoG or Steam.
2.) You can always increase your tier by donating more towards the end of the fundraiser! It might be possible (like last time) to increase even after kickstarter.
3.) The EE enhancements are post-production. The company was done and satisfied with the product. As time went on and they saw how loved the game was, they decided to give the game one last free update and made it possible to support D:OS for a longer time in the future.
4.) The whole point of the kickstarter is to give Larian just that little bit more funding they need to really finish off the game. It is also a great way to get feedback by more serious gamers that are willing to pay for the product many months prior to release.
5.) If there is a alpha/beta like last time, you can help with the initial bug squishing and content suggestions. Just imagine if we never got that little "key bag" and they all went into the regular inventory... *shudder*
6.) Last Kickstarter, Larian was VERY active with updating and informing everyone on how the project was going and showing us what a difference it all really made.
7.) Most importantly, you are going to be talking directly to the development staff. Programmers, composer(s), CEO. They read the forums often, just rarely get time to post.www.lar.net
for the CEO's personal blog.