If I had to guess, the 180 sets will work through 3.1, yes. Then progression will "reset" in 3.2, and they'll need a new set of scrip gear to get the rarest stuff again. The same will likely be true for crafters. A fully-pentamelded i170 crafter will probably need fewer upgrades come 3.2 to get to the new (presumably) 3-star stuff. However, if they continue to gate materials the way they've done so far, being ahead on crafting, at the least, probably won't hold too much value.