TBH, GUCs, while a very nice perk, are a disaster in general IMO. They should really just clear into any available seat at booking for all flights. These games we have to play to use them, frankly, are absurd. I get that revenue management has a large role in this, but at the end of the day, it's a zero sum game... and the goodwill they would earn from the DMs (or, perhaps better put, less bad-will) would more than outstrip the "lost" revenue by making GUCs easier to use.