Snag, what a great post. There is a lot of very important and useful information to be had there.
Concerning the quote that I chose, I just wanted to add that, while keeping it simple is an important factor to consider, especially if you want to be a working bass player, there are also some great players worth listening to who were master of improvisation and not playing it the same, over and over.
The one that comes to mind immediately is James Jamerson, the Motown bassist. This man had the improvisational ability to change his part every time around, without ever taking away from the music. Improvisation is an important aspect of playing that is worth spending some time on, especially if you have aspirations in the area of Jazz. John Paul Jones of Led Zeppelin also has the ability to subtly change parts each time around, without it being a distraction. Learning how to improvise on the spot in a tasteful way can reduce the boredom of playing the part the same way, each time around.
Of course, after saying all of that, it really depends on the role that the specific music you are playing demands. It is just as important to keep your ego in check. If the song requires or suggests simplicity, and you overplay your heart out, your fellow musicians might not appreciate it too much.