No I haven't faded away. I just recognize an impasse when I see it, and perhaps it was a misjudgment on my part to seek opinions critical of the writing on the author's own website... I still believe that Vin's survival instinct would be stronger than any qualms she might have over hurting someone, particularly if that someone was one of her captors.
As far as other options are concerned: how about moving a couple of cans under the ladder and using a Duralumin fueled jump to shove aside the rock? She used this ability on more than one occasion to toss dozens of men and horses and even Koloss like chaff on the wind. Surely that would have been enough to move a stone which had been placed on top of the shaft by normal men unaided by allomancy. Or what about using emotional allomancy on the guards waiting on the other side of the stone to get them to move it for her? She could have pleaded, or threatened, or tricked them (with the nobleman's help, willing or otherwise), along with a duralumin enhanced Riot or Soothe. I'm not saying these things were guaranteed to work, what I am saying is that trying anything other than potentially rendering herself vulnerable to her enemies would have been truer to her established character.
For those of you who have read David Eddings' Belgariad sequel The Malloreon, Vin's inexplicable choice here reminds me of the scene in that story where the Emperor of Mallorea decides to meekly join Belgarion's group despite being fiercely independent and arrogant prior to (another time I had to force myself to finish a series). Vin's cynical, hyper-cautious nature was one of the things that I enjoyed about her character. To have her character subverted in order to achieve a plot wicket is, I believe, a form of Deus Ex Machina.
And finally, there is a subtle but very important difference between being impulsive and being intuitive. You all are right: Kelsier was impulsive, dangerously so. But Vin was intuitive. She had an odd ability to take in the details of a situation, assess it, and react accordingly, all without her conscious mind coming into play, and usually make the right decision. Her intuition should have been screaming at her not to take her chances with the wine: to find another solution.