I came across a conversation today where people were regretting the early death of the Black Prince, because apparently everything would have been much better had he lived.
Unfortunately, even people interested in English history tend not to appreciate that at the end of Edward III's reign England was 1. losing the war with France (badly) and 2. almost bankrupt.
So unless the Black Prince was secretly a magician who could conjure gold out of the air - paper currency being a thing as yet unknown - he would have struggled with the same issues Richard II and his Council faced - that is, how to raise money without upsetting the easily-upset English taxpayer. And if you look at Edward's track record with his taxpayers in Gascony, it would probably not have been pretty.
A rather similar conversation can be had around Henry V. It is true that at his death the English military position had not collapsed (as it had in 1377) but the problems with money had already started. Parliament was not for splashing out. Not even for Henry V. Poor old Henry VI never had a chance - arguably his followers did extremely well to hold on to as much as France as they did for as long as they did.
If I am going to regret anyone's early death it would be Edward IV's. Had he lived another ten years Richard of Gloucester could have continued happily in Yorkshire, Henry Tudor would be a mere footnote in history, and a whole lot of sorrow would have been avoided.