The problem here is that brain wallets and paper wallets have become popular.

Brain wallets are always a terrible idea, either the pass phrase is too simple and easily cracked, or too complicated and easily forgotten.

Paper wallets are only useful for savings, if you want to spend the coins you should move the full amount.

As said elsewhere, if you use the stock client as designed, and don't use brain or paper wallets, then you should never lose coins.