IDEA's strength has always been that it is a great editor in addition to a great IDE.
I have a feeling that this strength has been somewhat neglected in recent times.
The most recent improvements that I remember were soft wraps and vertical indent guides (which are great, but have already been introduced in IDEA 9 and 10).
I can't think of any more recent significant improvements.
At the same time some bugs crept in, flaws are unaddressed and some great new ideas have not yet been implemented.
I am sure everybody has their own pain points here. Maybe just add them to this thread!
- multi-caret editing (IDEA-80056)
- some features of the "SmarterEditor" plugin could be implemented natively, my favorite is Alt-+ to split a string
- Editor history is botched after dragging a tab (IDEA-82948, IDEA-26333
- Dragging a tab into another split does not work if there are "subtabs" in that tabs current file (IDEA-97677)
- Navigating to a file that is already open in the other split (goto file, ctrl-alt-up/down in search result, go to bookmark) does not focus the file (but just brings the tab to the front) (so I am temporarily disoriented and then forced to use the mouse) (IDEA-90311, IDEA-116523
- editor splits are still awkward to handle (try and move the current file to a new vertical split)
- macro implementation is so simple, it's nearly useless
- toolwindow modes are very strange (IDEA-76424)
- html/xml editor behaves fundamentally different with regard to auto-inserted characters (WEB-11053).
Plus these are more than a few other issues regarding editing, character encodings, tab handling, completion etc.
Please give these issues higher priority! The good thing is that most every of your IDEs is going to benefit from it!