Check out this post about Misty's narrative scripting tool
I love writing games in spreadsheet format. Letting me modify a spreadsheet directly allows me to make my own dashboards and text data visualizations using spreadsheet features in Google and Excel. I also love having the ability to add columns infinitely to track all sorts of data for the different stages of production.
I don't tend to always begin writing game scripts in a spreadsheet, though. I usually start in some tool meant for writing specifically - often a screenplay writing program - and then move it to spreadsheet at some later point. I've also worked with teams that would automatically process google docs and fountain-style screenplay markdown into a spreadsheet at some point in production. At that point I move entirely to writing and editing in the spreadsheet.
Lots of people dislike writing in spreadsheets because the column UI and the busy interface are not a particularly luxurious setting for writers. That said... google docs and screenplay editing tools are often poor approximations for the game's UI. It's hard to know in any of these tools whether you're in danger of overflowing the UI, or whether text-dense boxes look "bad" in the UI or not. You'll have to write a bit, get it in-game, test it, and then make decisions about your ideal character count for dialogue boxes, and so on.
When I move a script to spreadsheet, I usually add a length calculation column to calculate the character count of each cell. I then use conditional formatting to highlight cells that are likely to feel "too dense" in the UI, and then I go check those cells specifically. But this is never a sure thing... it would be better to just see all the text in-game while you're working on it, wouldn't it?
I have been lucky enough to use text-UI test apps several times on different games. The ideal text-testing app will just render the dialogue parts of the game only, and let you load any script into the UI that you please. I had one of these on Where the Water Tastes Like Wine a long time ago and it was essential to hitting high text quality in that game. You can read about what using it was like here.
I just read an excellent blog post about a text UI test app created by Misty De Méo, who is working on a fan translation of the game Magic School Lunar. The app looks extremely convenient and is specifically designed to deal with the localization needs of a game with limited-size, unscrollable text boxes and fixed-width fonts. These limitations make it super important to visually check every single text box in the game, and Misty's tool makes doing those checks as easy as possible. It's very cool!!
One of the things that makes narrative design in games so difficult is that each game is usually unique enough that it could genuinely benefit from a great deal of custom narrative tooling. I've been very lucky over the years to work with engineers who are very good at making custom tools as quickly as possible. My husband Brendon made a ton of custom narrative tools for Skin Deep, mostly focused on the localization and narrative bug-fixing processes. Narrative workers who can code their own tools are insanely powerful, but if you can't do that, the next best thing you could get is a ride-or-die engineer friend who is willing to bash out janky tools for you as fast as possible. I'm definitely going to keep Misty's blog post in my back pocket as an example for future narrative tooling!