The problem with this campaign as I see it is the lack of far reaching and visionary stretch goals. The 2.2 million stretch goal is slowly coming about and then there is one at 2.3 million but what happens after that? To increase the amount of backers I think you need to have some more daring stretch goals at higher amounts of money to appeal to us to give more.
Look at how Wasteland 2 did it. They had some stretch goals pretty far away (right from the begining) that they finally reached. For exemple, "if we make 3 million dollars the game world will be bigger than Wasteland 1". And if we make more than [insert huge amount here] we will include mod support on release. That was promises that really triggered people.
Those goals made me dubbel my pledge. As it is now you get the feeling that all the goals are fullfilled or almost fullfilled and that there is no reason to increse your pledge or to nag on your buddies to also pledge. But if there was a bigger goal more far off for exemple, "if we reach 3 million we will make the gameworld bigger than Baldurs Gate 2", that is something that would really get people excited and increase their pledge.
I know how a backer thinks. With Wasteland 2 I started with a pledge at 15$ but kept increasing it all the time because InExile kept adding cool and far away stretch goals so that I saw the necessity of me pledging more. I ended up pleding a hell of lot more than 15$ and I think that is something that could happen with this campaign as well if you start to talk about how the game could be if you reched 3 million, or 3,5 million or whatever.
But as it is now when the highest stretchgoal is always just 100k away which gives you the impression that the game as you want it is almost fully financed and that there is now reason to pledge more.
So please, be visionary and talk about what you wanna do with Project Eternity if you reach 3 million dollars or more!
I have some suggestions for future stretch goals that would help getting people excited and to increase their pledges:
*If we reach so and so you will be able to choose between turn based and real time combat
*If we reach so and so the game will include more dialog than PlanescapeTorment
*If we reach so and so we will add modsupport etc.