I'm so sorry to hear that you're also going through this. This would be my #1 regret right now I think.
I feel like my one MOH wants no involvement, and I almost feel bad asking her to do something for me because it really feels like it's not a priority at all for her. She even told me the other day that she just wants to be a guest at a wedding for a change. For some reason she's always a bridesmaid or MOH. It's not my fault, but it made me feel really bad when she said that. I told her that I didn't want much from her, just basically stand by my side, make sure my train looks nice, be with me on some pictures and help me out getting the music for the reception together before we leave. I told her she'd be sitting with her date during dinner, and she doesn't even have to enter the reception with us, so technically she is just a guest with a couple of exceptions. I still feel bad about what she said though, it really hurt my feelings.
It would have been better if I had no one by my side to be honest. It also would have been cheaper on me since I paid for the dresses. I guess I just felt totally unappreciated. I've been super low maintenance with them, didn't ask anything, paid for their dresses and then I get complaints.
I guess sometimes depending how bad the situation is, it's warranted telling people that they're not on the bridal party anymore. I guess for people causing trouble, they probably don't even want to be there anyway, so it might even be a relief for them. Would it cause drama with everyone else? probably, but at the same time you have to look out for your own sanity, and if this person is driving you crazy, it's not worth the stress.
It is true that weddings bring out the worst in people, and I think this applies to all weddings, no mater how young or old you are, whether you have a DW or a local wedding. Sometimes on these forums I don't even get into all the drama we've had along the way. I can say for sure that I'm a lot less nice coming out of this wedding than I was going into it. I realized that I put a lot of effort into my relationships with people but I don't always get the same back, and that's very disappointing. Those are the times when I miss my home country, because I feel like relationships over there are much more valuable.