Apple Pencil 2 wishlist: The end/cap to act as an eraser.
The only way to include something like that would be to have a "dumb" version of the erase that doesn't have anywhere near the same sensitivity or control for erasing as the nib end. It might save you a few fractions of a second here and there, but it's hardly a priority vs. a tap or a gesture to change the mode to erase.