So essentially an abuser has to create 10 accounts (total 60SP or about $270 delegated SP and 2SP) then just spread votes amongst them.
If they have the knowledge to abuse the delegation system then they have this knowledge already.
A hard fork is not always the answer. At least not one that is trivially circumvented by the bad actors
It would definitely curb the "manual" abuser, who has 3 to 5 accounts and they manually click upvotes