Your wording suggests that I would assume the ITP, which would then imply rejecting the value of identity. But actually my reasoning goes in the other direction: since I don't find personal identity to correspond to anything fundamental, my rejection of it causes me to arrive at something ITP-like. But note that I would not say that my rejection of personal identity necessarily implies ITP: "the total amount of positive and negative experience is all that matters" is a much stronger claim than a mere "personal identity doesn't matter". I have only made the latter claim, not the former.

I have the same reductionist views of personal identity as you. I completely agree that it isn't ontologically fundamental or anything like that. The difference between us is that when you concluded it wasn't ontologically fundamental you stopped caring about it. I, by contrast, just replaced the symbol with what it stood for. I figured out what it was that we meant by "personal identity" and concluded that that was what I had really cared about all along.

That does provide a possible reason to prefer the child with the more ambitious preferences, if the net outcome for the world as a whole could be expected to be positive. But if it can't, then it seems obvious to me that we should prefer creating the non-ambitious child.

I can't agree with this. If I had the choice between a wireheaded child who lived a life of perfect passive bliss, or a child who spent their life scientifically studying nature (but lived a hermitlike existence so their discoveries wouldn't benefit others), I would pick the second child, even if they endured many hardships the wirehead would not. I would also prefer not to be wireheaded, even if the wireheaded me would have an easier life.

When considering creating people who have different life goals, my first objective is of course, making sure both of those people would live lives worth living. But if the answer is yes for both of them then my decision would be based primarily on whose life goals were more in line with my ideals about what humanity should try to be, rather than whose life would be easier.

I suppose I am advocating something like G.E. Moore's Ideal Utilitarianism, except instead of trying to maximize ideals directly I am advocating creating people who care about those ideals and then maximizing their utility.

Even if we accepted IPT, we would still have good reasons to prefer not killing existing people: namely that society works much better and with much lower levels of stress and fear if everyone has strong guarantees that society puts a high value on preserving their lives.

I agree, but I also think killing and replacing is wrong in principle.

I stopped consdering the Repugnant Conclusion a problem after reading John Maxwell's, Michael Sullivan's and Eliezer's comments to your "Mere Cable Channel Addition Paradox" post.

I did too, but then I realized I was making a mistake. I realized that the problem with the RC was in it's premises, not it's practicality. I ultimately realized that the Mere Addition Principle was false, and that that is what is wrong with the RC.

While this phrasing indeed doesn't make any mention of "persons", it still seems to me primarily motivated by a desire to create a moral theory based on persons.

No, it is motivated a desire to create a moral theory that accurately maps what I morally value, and I consider the types of relationships we commonly refer to as "personal identity" to be more morally valuable than pretty much anything. Would you rather I devise a moral theory based on stuff I didn't consider morally valuable?

If not, demanding the "link" criteria seems like an arbitrary decision.

You can make absolutely anything sound arbitrary if you use the right rhetoric. All you have to do is take the thing that I care about, find a category it shares with things I don't care about nearly as much, and then ask me why I am arbitrarily caring for one thing over the other even though they are in the same category.

For instance, I could say "Pain and pleasure are both brain states. It's ridiculously arbitrary to care about one brain state over another, when they are all just states that occur in your brain. You should be more inclusive and less arbitrary. Now please climb into that iron maiden."

I believe personal identity is one of the cornerstones of morality, whether you call it by that name, or replace the name with the things it stands for. I don't consider it arbitrary at all.