It isn't all international travel that is precluded from the free upgrades, though it may seem that way. On CO you can be upgraded for free on any flight that is not marketed as BusinessFirst. There are a number of flights to nearby international destinations (Canada, Mexico, the Caribbean, Central America and Northern South America) where upgrades are possible. And within Micronesia upgrades are an option as well. But you will not get upgrades for free on the long-haul trans-oceanic flights.

As for the redemption you're looking at, I agree with Kagehitokiri that the service is better on the other airlines he mentions, but I'm not sure I'd be willing to add an extra stop just for that. If the seats are available at the lower redemption level I might add the stop, but not just for the service difference I don't think.

If you share the dates you're trying to find seats on we might be able to help recommend a specific itinerary.