I know that a lot of us can see the bigger picture, that helping everyone keeps it healthy for the majority, but I agree, there are always going to be some who abuse the system and leave a desolate landscape behind, like any exploitative-extractive industry does.
I don't have an ultimate solution, but what if flags were changed so they they were decoupled from SP? Everyone's flag is equal in weight. Then the damage is decided by HOW MANY people flag instead of one whale being able to decimate someone they don't like, minnows being afraid of retaliation, true abusers being taken down by a concensus? I suppose big whales could make a bunch of alts. But if little fish were unafraid to use them, I'd think you'd get a lot more participating in downvoting spam which might balance it out.
It was just an idea that came to me, and I'm not a techie, so there might be something that would make this not work that I don't know.