I don't know, what other users think about it, but for me the scrollbar also showed how large a file is or what part of the file I am viewing at the moment. If the scrollbar's thumb was at the bottom, nothing was below the visible window ("viewport").
Currently this is broken and IntelliJ calls it a feature. I call it a bug or GUI blooper. I know, that some people have asked for an option to let the user edit a file in the upper third of the editor window - even on the end of the file. But why bother all the other users, that liked the existing behaviour?
Please make it possible to get back the old behaviour, e.g. by adding an option.