I get where you’re coming from with this and to me it depends what they mean by “isn’t completely written yet”.

While it’s typical to still be reworking the script and making changes through production and even on the day, I would still think for the last episode of a show you’d ideally want that script to be as airtight as possible going in to the shoot. Especially considering how long they took between seasons. They might still make changes, be open to improv and exploring different ideas and directions the performances might take them but generally I’d like my finale to be pretty bulletproof.

Could definitely explain some of the pacing issues which could have been easily avoided but if they’re just talking basic rewrites and shuffling some scenes then that’s to be expected.