I honestly think it can go any direction. I've seen tight-string tribes fall because of one bad decision by the duke's. I've seen singular players cause mass wars involving the whole world. It can really go anywhere. If we're going to predict, my own here:
When it gets to the point where it'll be family tribes on family tribes, it depends. Turtle will probably run solo when morale is removed, and continue on the way they have been. They're fighting wars on fronts that involve specific members, not the entire tribe, which is what is giving them their title of current best. The Weed vs. Turtle war, believe it or not, was only the K34 SE and K35 SW members verse them. With the numbers Weed had, plus their alliances, it was really a fair fight, but like most tribes against a bigger name, they legged it.
Right now we're seeing a full commit to a war from Turtle, and you'll soon see what they have to offer in the way of resistance/play. I think it'll come down to Turtle vs. who ever wins out of Orc and CORE. Cruel is a tight tribe, but I've not seen or heard of any of their play like I have seen of Turtle, Orc, and Core. Orc are way too quiet, but their stats speak for themselves, and the launch on CORE was an amazing start for them. They have what it takes. CORE on the other hand have the numbers. They honestly are a powerhouse because of it as well. With that many members and that difference, they're pretty hard done by simply because they're a "Family" tribe. I've seen families last years, being part of the leading tribe of W31 for 18 months, where 18 months the number 1 spot was Hell!, and then just 3 months later, for 15-16 months, their second tribe Fire! rose to 2nd place. Family tribes can last, and can win worlds.
Time will tell, and the war stats will show, but I honestly thing it'll be Turtle vs. the winner of this war in the late game. As for the comment about all the tribes teaming up against Turtle, that's already happened, and the culprits are alreadying rimmed/being rimmed as we speak. Hippos, Weed, PIG Family. The numbers may be there, but they won't have any co-ordination like Core does as a family.
Only time will tell.