I'll answer my own question.

I think the past few negotiations have improved the QOL, pay, etc of the bottom third of each category. (Notice I did NOT say the bottom half of the seniority list.)
I think by doing so, they have improved the lot of the other two thirds by giving them more choices, as in bidding reserve if they want. For the past at least the past 5 months, anyone in my category who wanted to hold a regular line could.

So my answer would be everyone! I know, a copout!

Denny