Thanks R2C, that is good framework for a conversation. I'll give it some thought. My initial reaction is that she would take that offer as a way to buy more time and just continue living her current WW lifestyle. I can already see her rolling her eyes at "That is what I am looking for and that is the kind of person I will be with." She does not see me as the prize and the threat of me walking doesn't hold much weight. It's the main reason I feel that filing D is the next logical step here. I am ok with ending the MR at this point, and if she can turn things around during the entirety of my state's 6 month waiting period I would consider not finalizing things.
I've done a lot of work on myself the last two years. Much of the advice here and elsewhere for those in my sitch is to build yourself back into the person you were when you met your W (or better) and be prepared to leave if things don't improve. When you turn back at the door what you'll see is no longer someone you're afraid to lose, but someone who isn't providing you with the value you expect for yourself in relationship. Obviously we're not talking "you don't make my favorite dish often enough", we're talking "I don't trust you to care for our kids because you have a drinking problem". I'm not "that guy" yet but I feel I'm close.
MY IC and parents have both said to me constantly that "the kids know something is wrong". We don't have a high conflict marriage (no fighting in general and none in front of the kids) so I've pushed back on that idea. But last night D6 came to me before bed and said "Daddy, one day can we take a trip as a whole family where mommy comes too? We never do that." To which S5 responded, "We did that one time when we went to <vacation>". That trip was one year ago.