Isn't it necessary for integration that everyone involved should cooperate and agree on trying it? I don't know, just a question that occurs to me. Also, I guess the idea is that the alters tend to be extreme and have so defined characteristics because the psyche is fragmented, and those feelings (and actions) would become less extreme in a construct where they become more balanced?

As far as there being a supportive reason why alters exist and that perhaps it is better that way - I guess that was the case originally when the initial traumas and dissociations happened. But if you are no longer in those situations and don't need to actively deal with similar things, perhaps it does not necessarily have a functional role to be divided?

I also wanted to add to the part where I said that you have come quite far, that you definitely seem quite functional in terms of being open to all sorts of feedback and considering it without getting defensive. I remember there were suggestions earlier on your threads that listening to all the different (and sometimes contradictory) opinions may not be a good idea and you should choose one standpoint and not discuss your issues so openly and publicly. For me, your openness and ability not to get defensive and attack people for presenting different opinions is a very healthy feature, one that probably helps you to uncover all these things and improve, try new things in spite of skepticism and current beliefs.