I only partially fit this category since I DID buy the Blackwell-bundle BUT I was a very difficult sale as:
a) I mostly just bought it as I'm researching adventure-games so wasn't really that I was interested in playing it. (it was only while playing the full version that I realized I enjoyed it)
b) Tho I played 1st demo as it came out I only bought the bundle years later.
Reason I was such a hard sell:
a) I was under the impression the entire series looked like Legacy, it was only at your blog-post on real-life NYC locations that I saw some night-time shots from Unbound and Convergence that I was like "hey that's much better than I remembered it!".
b) I did not like the Legacy demo as:
b-a) I hate exposition, I'm perhaps more sensitive than anyone on the rule show don't tell.
b-b) after the exposition when I was ready to play the demo was over without a single trace of meaningful interactivity, I felt a bit cheated having invested this time downloading the demo and reading up on that exposition and then not getting to do anything meaningfull, it felt like reading up on the rules of a sport and then being denied playing it.
c) a bit annoyed at the stretched out picture on my wide-screen monitor which also made the mouse move faster horizontally than vertically, it felt like there was some kind of forced mouse-acceleration on (tho it could be the widescreen stretching that gave that illusion), this doesn't affect my decision if I like where the story is going but it was a turn-off.
d) perhaps a bit bad luck on the reviews, I felt the adventuregamers review (which tend to be the only reviews I read) on unbound was unfairly harsh they immediately attacked the fact that you stated it was a lower-budget game (I wondered if they even would have complained had you not mentioned that, I certainly didn't notice the game was of lower ambition than the previous game, I thought the opposite),
GR on the other hand got a amazing review on adventuregamers (which I felt was a bit overpositive, not in final score but just that the text failed to really explain it's limitations, hmm come to think about it maybe I should change review-site as I never seem to agree with them

)
as for GR I wasn't impressed gameplay-wise with the intro either BUT just the fact that every city BG was stylized made me think that if I buy the game and invest some time playing it then I'm sure I will learn to like it, I don't think you should ever have to LEARN to like something BUT video-games are still a long way from reaching that instant-immersion that some movies achieve so until then it needs at least something to tell me "you'll probably learn to like this game if you give it time",