I don't think Nicholas or Michelle would have appeared as cameos. Potentially ASH, which is unfortunate since we will never get a reunion between Buffy and Giles. 🙁
They would definitely have touched on the impact of Willow's spell and the many Slayers around the world! The cinematography would have been more modern, shot digitally obviously.
But past that, we don't know if the plot or the characters would have been good or bad. All I know is that there would have been a bunch of people ready to criticize every single plot hole or other issue with the show to validate their preconceived expectations. This happens all the time nowadays, as some YouTube channels are entirely focused on doing just that and farming the views (and money) and outrage it generates.
Despite all that, though, I would have loved to see what they could have done with the show. Sadly, it's the third time a resurrection project failed. Time is running out for some of the original actors. Imo, this one was more disappointing because it got so close to happening.
Don't waste your time, man. There's no point arguing with people who are completely ideologically captured. They'll interpret everything related to modern media through anti-'woke' glasses. 😉 There's no constructive discussion to be had. Trust me I tried.
From our own national treasure, Margaret Atwood. ❤️ I only watched a few episodes of the show, but the novel is really good. I recommend it!