Probably should definitely only be an option to set in preferences.  Generally in code editing I like very fine grained undo/redo.  Perhaps just a MUCH larger undo/redo buffer would be the solution.

Don't forget control-e/a and other abbreviated emacs keybindings are natively supported by Cocoa @Dirknilius.

https://github.com/rsense/rsense is a great fix for this enormous need.  Ruby (and Opal - Ruby to JavaScript Transpiler) are primary languages here and Rsense works a treat for TextMate at the moment.  Also see: https://github.com/rsense/rsense.tmbundle

Elia and Edubkendo would be more than happy to help with any problems: https://gitter.im/rsense/rsense