One thing GRRM notes about wanting to use Wordstar is how modern word processors nowadays will auto-correct as you write, either inserting a capital letter, or correcting a typo. Which no doubt can be annoying. The few times I've had to use a word processor I always end up gnashing my teeth at the "useful" features they have on offer.
I'm of the opinion that software should make the fewest assumptions as possible about what the user wants to do, ideally, software should be dumb not smart.
[1] - https://www.vice.com/en/article/wxdeay/the-dune-screenplay-w...
[2] - https://techcrunch.com/2014/05/14/george-r-r-martin-writes-e...