One thing that bothers me about new code editors/IDEs is that their developers really don't do a good enough job researching and deriving inspiration from the editors that already exist.
For example, I have yet to find any modern editor that draws inspiration from the brilliantly designed ideas used in Plan 9's 'sam' and 'acme' editors.
For example structured regexps, 3 button mouse chording, and the 'plumb' feature thats basically a context-aware, smarter version of a unix pipe between two executables.
I mean i can go on and on but another thing that i find absolutely annoying about newer editors is that they all use Webkit as the base of their apps core foundation.
This makes it irritating to consider trying to make changes to the code that I believe would overall improve the editor and make it more useful. (at least as far as im concerned)
I can literally make a list a mile long of things I like in other editors and wish i could see condensed into one ultimate code editor to supplant all code editors that had come before.