I think the idea is great. I also agree it should be an option in the user profile.
Furthermore, I'd suggest that the default be "off", i.e. do not show rep. details. The reason for this is that a novice at the Monastery already has so much new stuff to discover. When the novice starts to find his/her way around here s/he will become more curious and start looking for personal configuration. It will then be a new discovery to find the detailed rep. information.
It should also be verified if this would have a negative impact on the database performance, in which case I would tend to say it's not worth it. (Performance is currently acceptable but not brilliant.)
Everything went worng, just as foreseen.