I don't necessarily think a 'rating' system is a great idea in my opinion, but if others are all for it, it's definitely fine with me. But yeah, it could spark unnecessary tension over such a little thing..I'm afraid that sometimes the system could be misused in a mean way by an upset member.
And anyways, I do like the Tier system

If we could find a better way to improve what we have now (as in, not just Cspace doing the rankings..), I'm sure it'd be fine.
But in anything we use, I suggest there shouldn't be an option for anyone to remove a ranking/degrade someone. That in itself is what I would be most worried about =\ If there was a system were rankings could be added and not removed, then a member wouldn't have too much to get upset about.