I had over 8000 items on my enwiki watchlist, and have thousands more on other projects like Wikidata or Commons, and when going through and removing the items via https://en.wikipedia.org/wiki/Special:EditWatchlist, the save changes button is at the entire bottom of the page, which forces me to scroll the entire page to get to it, even if I am only working in a limited section of the list. Its a terrible UX experience. I recommend floating that in the top right corner like we do on the save button in VE -- that would make it much easier to remove a group of items and save, without spending 10-20 seconds managing a long scroll (probably even worse on Commons and Wikidata).