I don't see why a system which treats N flags the same as a 1 flag would improve things. If 10 people are upset at what someone posted compared to 1 person being upset, those clearly have different weights, IMO.

Note, I said "person," not account. I think an identity system may need to be built into a reputation system for it to really function effectively. See my post on Privacy, Identity, and Human Flourishing for more thoughts on that.