1st: I sat myself on IM, I am very aware of my place in the raid and if my mistakes are making things more difficult, I will take action against myself. I am working on improving my play on a spec I have NEVER played before, while improvement is happening, I am not up to the caliber I should be, so until that time, I will ALWAYS be the first to volunteer to sit if the group needs to maximize for a progression kill.
2nd: My answer is maybe. We can explore options to possibly have a 3 strikes rule or something similar. Say a person dies 3 times in a row to the exact same mechanic, then yes, we can sit that person. It's an idea to explore further, but ultimately, I will leave the decision on how we proceed with such a rule to FTFK and Lyntha, at this time, this is their raid group and leading it how they want to lead it is important.
3rd: as far as progression goes, no matter what route we take, there will always be someone that is unhappy with it and would rather focus on something else. I think our end game should be to always be working on "new" content that the team has never seen before to help waive off stagnation. Most people seem happy as long we we get "ahead of the curve" achievement every tier. Something to discuss after raid with those that hang around.