the plotting has the same accuracy as it's shown on your screen the same drawing can be easily plotted in different paper formats etc. The productivity of using electronic files for drawings is obviously greater comparing to the traditional method: changes are done much faster the drawing can be sent to plotter and you have time to work on another task no special paper, special pens, etc. It also speaks about your company's 'personality'. Creating an electronic symbol library it can be an one-time process with some further easy-to-make updates.
So I think you can take a look on what your company has used until now in its drawings and try to be consistent with that. Speaking about electrical symbols, I can tell that I've seen many different ways to show the same device and many different styles of doing electrical schematics, depending on company, even if there is an effort from ANSI/IEEE or CSA or whatever standards organization rules a piece of land somewhere. You might find some software with electrical symbol 'libraries' that can work with AutoCAD, but I know that these are not a part of AutoCAD package you can purchase from Autodesk.
There is not such thing, as far as I know. You're looking for a version of AutoCAD dedicated to the electrical engineering stuff.
