CodeEditor provides a nice feature on top of ace: a "status summary" box at the bottom with all annotations for the current code. This is implemented with ~180 lines of JS code in the CodeEditor module.

I think it would be great if this was moved upstream, toggled with a config option (e.g. aceEditor.session.setOption( 'showStatusBar', true );). Aside from the obvious reasons for doing this, I'd specifically like to use it in the AbuseFilter rules editor (which grabs ace from CodeEditor).