Thanks for this post. Your MLCer sounds a lot like mine - dragging you back to court over an imagined wrong.
I believe that my xh's MLC has been prolonged by a serious and life threatening illness which was diagnosed around 3 years in. Against all the odds he survived, but dealing with health issues tends to slow down the process further.
As Job and others have observed, in most cases this crisis was a long time coming, and it isn't usually over quickly. I would say five years is a relatively short crisis - assuming they ever come through it.
M xh is reconnecting with his children - for a long time he didn't see the necessity for the hard work, and patience. Now he gets it, and he is in their lives again, This is a good sign for me. And I am pleased for all of them. He was a great father and role model until this crisis struck.
Even if he continues to make progress I am not sure whether I just want to make my peace with him, or to have some sort of on-going 'friendship'. As he is remarried, nothing more would ever be offered, and like you, the thought of any close relationship with him scares me!! I have moved beyond wanting him back in my life in any major role. Indeed, in my case, I love my single life, although I am really happy for people who do meet a new person.
One thing I have taken away from all of this is not to sweat the small stuff. The other is to be as kind as possible to other people, without being a doormat.
I wouldn't wish dealing with MLC on anyone, but you do grow!