With a 'C' corporation, you can easily give different heirs different amounts of stock, or different type of stock -- voting shares to one person, non-voting shares to another, ... There's much more flexibility.
It's too much trouble and increases the possibility of a tax audit.
The IRS will never come and tell you who is likely to be audited, but generally, filers (who take home-office deductions) tend to be more frequently audited,
If there is any question about the solvency of the person paying, they may want to forget the tax benefit and characterize (those payments) as child support.