I understand your wait and see attitude on this one - complete reunification isn't going to be an easy task.
OTOH I do think it needs to be pointed out that this is the first time since the 1970's that the APA has been recognized by groups which are officially part of the Anglican Communion (NACDP and AMIA); even more importantly it's also the first time since 1875 that the REC has been so recognized. I know you aren't terribly happy with the AMIA, but in this case that doesn't matter considering the support and influence which they have among the Global South Primates. What does matter here is that this joint letter to the ABC not only signifies the potential for reunification with at least some of the Continuing Anglican Churches here in North America; but also gives the Eames Commission leverage toward recognizing a valid Anglican presence in North America which covers the entire spectrum of Anglican theology.
I agree that this is the hope. I'm not really taking a "wait and see" attitude, so much as recognizing that talking about unity, and actually doing something about it, are two entirely different matters.
I would certainly welcome a reunification of these various groups, as it could form the core of a new province. However, we cannot avoid the difficulties that led to these groups into leaving in the first place -- except in the case of the AMiA (and only partially, there) homosexuality wasn't the cause.
The problem will be in satisfying the divergent doctrines of these groups (e.g., woman priests, style of prayerbook, etc.) so as to avoid one or more groups saying, "we left once, and by God we can leave again." Given that the various splinter groups have a reputation of being cranky, and that even the orthodox Episcopalians tend to be impatient of crankiness, I think this will be a major issue.