I think this might run into the perennial free travel-vs.-upgrades debate, so for full disclosure I'm on the free-travel side. Have spent about 1.6 million or so miles lifetime and -0- on upgrades (though I've never said no to an operational upgrade!)

Intra-Asia is indeed a good deal because it includes Micronesia, Cairns and Bali through CO's GUM hub. Using stopovers and jumping off from gateways like Manila, I've done itins like MNL-GUM-MAJ(stop)-GUM-YAP(stop)-MNL at 25K, or MNL-GUM-PNI (stop)-KSA(stop)-GUM-MNL. Was using CO miles at the time, so NW may be harder to redeem, and YMMV.

Even better was jumping around the South Pacific on NZ using UA miles out of PER or CNS at 20K a RT if lucky. That put places like PPT, RAR, NAN, APW and New Zealand within reach.

U.S.-Asia can be a good deal for some. If you're on the east coast the equivalent paid ticket would be more than the west coast, and being able to use stopovers (like HNL) or open jaws can add value, as can staying longer than 30 days. A paid ticket with those parameters usually costs a good bit more than the lowest sale fare.

Alaska at 25K is one of my favorite awards, especially in September. Still beautiful, most of the crowds are gone, everything is fall-like and ANC car and hotel prices have gotten much more like the lower 48 in the last few years.

Canada can also be good in some cases, as you avoid some of the taxes with paid tickets and might get to go somewhere like Prince Edward Island that doesn't get a lot of sales.

Whatever you do, don't count on sitting on a big pile of miles long-term without the value getting whacked. We've seen a lot of erosion already, but I think the rate of damage will accelerate with the start of the baby boom retirements.