You can install IdeaVim in PyCharm. I've been using IdeaVim with IntelliJ for 6 years and could never go back to non-vim style editing. This plugin provides the best of both worlds.
Yes I have used plain Vim as a text editor for many years. It's a great text editor. I know it was also used for writing code back in the old days. For working on large modern JVM codebases, however, Vim is a toy in comparison to IDEA. Vim is for manipulating syntax. IDEA has advanced semantic features that will remain far outside of Vim's domain.
Not OP but I’ve been using ideaVim for many years now and I can say that it’s quite good. It even uses my main .vimrc file and handles most of the things very well.
It IS much better than when I tried it. It parses your vimrc with and matches simple patterns to support the subset of features it does support but it doesn't really have an interpreter although one was discussed
Which means no plugins for example or complex viml. Presumably this would simply be ignored not broken.
Another approach for a different environment that seems more interesting https://github.com/lunixbochs/ActualVim I don't use sublime so I can't report on how optimal it is the idea of using an embedded vim instance is certainly interesting.