I'm really struck by those saying "there was a reason it was done that way" and that everyone should respect the wishes of the willer.
In my experience, no reason at all has been given or figured out a thing all. Just a big old blank empty space where you thought your parent felt that you and your siblings were of equal standing/value/whatever.
It's difficult to describe where this leaves you feeling, but it's not nice, even when you don't want or ask for the money to be divvied up evenly.
When the sibling chooses to keep the money and not even it up, that sibling seems invariably to feel on some level, albeit subconscious, that the uneven will was justified and right in some way. This causes a shift in the landscape of sibling relationships that's is pretty toxic in the long term.
When the sibling does choose to even it up, there are all sorts of complicated emotional legacies involving gratitude, beholdeness, generosity, fairness etc, and the ever lingering fuck you from the parent.
If you are making an uneven will, make sure enough you at least explain why. Oh, and don't make your shafted children joint executors with the favoured ones, because that's just plain mean.