@allevato Thanks, this really helps a lot!
@Slava_Pestov The problem with UTF8 is decoding and traversing it. While doing that is relatively easy for single codepoints, I have yet to learn about how to deal with characters consisting of more than one. I'll think about it though.
Thanks for the article about gap buffers though! Their resizing doesn't seem too difficult to implement so I may switch over to one. Might result in better cache locality or something :P