I think one thing to keep in mind with the above games, in particular, is without Kickstarter they likely would not exist today due to the costs involved with creating the game. Big boxes on shelves is not a model that works well in retail stores. Lots of little boxes that take up less space is where the profit lies (Magic and X-Wing are great examples).
For KDM. The base game is around $400USD, however for the full experience with all game play expansions will set you back over a few thousand dollars (the gamer’s bundle was $1650). Investing that much money into anything will make people, well, invested. I personally liked the idea of the game play, but was not interested in the theme or willing to invest in the full experience.
I definitely agree that the stretch goal creep can be massive with Kickstarter games, however I think another problem at the moment is projects are put up at a value that only makes sense if the project smashes the goal rather than funding at 100% to unlock pre-planned stretch goals. It rings hollow when you look at the project.
Overall, I think Kickstarter has been good for the board game industry. Love or hate it; it has allowed some companies like CMON to have an effective pre-order system with savings to the customers (A CMON Kickstarter pledge plus shipping is cheaper than the retail version of the core game in Australia). Large scale games like Gloomhaven, The Edge: Dawnfall, Middara, Folklore: Affliction, KDM and Sine Tempore that would have been difficult to get publisher backing due to game scale and complexity are being funded. This is increasing the number of RPGs in a box available for those interested in a game with a story outside of PC games.
As for hype. It definitely happens and if you look at Stonemaier games blog you can see why the good projects try to hype their games (PS. I am glad this was mentioned in the group discussion, I have been getting a lot out of it). The slot a game sits at on BGG on the hotness list has a fairly direct link with games smashing Kickstarter funding goals. From a backer perspective it is worth taking a step back and evaluating the project on the information and not the hype. Keep in mind that you need to wait a while for the hype to die down when big games are released as well before you will get a well rounded review. This is because again the higher on the BGG hotness list the more likely backers can sell their pledges for profit.
At the end of the day Kickstarter is a risk of investment based on whether you believe the creator can live up to your expectations. The bonus for board games is most will have rules to read through so you can get a good idea if the underlying mechanics work. Several will have print and play or TTS scenarios. Personally I have been burned and pleasantly surprised by the projects I have received.
In my opinion the biggest benefit to backing projects that fit your personal niche is it is more likely another project will be created in the future that you may find interesting. You are effectively voting with your wallet and saying there is a market available for a specific theme, mechanic or style of game.