Within the financial communities, there is a concept called "seasoning" of money. It refers to money that has sat in a bank account for 6 months or more. When applying for a mortgage, banks will often look to see if the money you have in your bank accounts has seasoned. If it hasn't, it can prevent your loan from going through.

What you describe is not that different from the seasoning of money. Perhaps requiring a seasoning of staked Steem would help mitigate some of these issues in the future? Perhaps a seasoning time of 3 months before it's used to vote for witnesses?