Python, Janet, Haskell, and Hare were the filetypes I remember either being unsupported or not working well. I need to be able to depend on basic language support from my text editor, even when I work with niche languages.
I've been using Python with tree-sitter on neovim for many months. It's great, and has a lot of improvements when compared with the old syntax system.
Re Hare: I haven't even set that one up. Setting up a new tree-sitter on neovim requires extra work for each tree-sitter, and that's definitely a flaw that needs to be addressed.
