You do realize, of course, just how quickly 20 times your NW in Aid is going to wreck your Trade Balance, don't you? Once taxes are factored in, it would take 2-3 times as many Soldiers for the War Hero to kill the Dragon as it would had the individual Provinces just sent the Soldiers themselves.
Or perhaps you mean if most EVERY Province in a Kingdom was a War Hero so that they could send massive hordes of Soldiers into the fray as Utopia-brand Dragon Chow... Which would be kind of awesome, excepting for the fact that they pass up bonuses from other Personalities that are actually of some use in situations other than killing Dragons.