Definitely, write the conscience post! I don't have a ton of SP, but I'll promote your post where I can.
So you're right - assuming pessimism here is rigging the game a bit. See my reply to @jholmes91 on this post; basically, if the Type-1 voter can put one of her favorites into a tie, and she believes that other voters like her preference also, then her best response may be to vote her favorite since in expectation (given her prior beliefs of others' preferences), it will win.
I assumed pessimism for 2 reasons:
- It's easier.
- I'm skeptical of the idea that people are Bayesian decision-makers! There seems to be a lot of empirical evidence that they are not; see Khaneman and friends and Prospect Theory.
I have a hunch that your model of vote-your-conscience could act as a proxy for assuming some sort of more-complicated belief structure. If I really want to vote for what I like, that's at least a little bit like believing that others are going to vote for it. But it tells a cleaner story and is easier to analyze, which I think is valuable.