If you're that worried about your replacement not being able to understand your code, either change the code or comment the bejesus out of it. Or more accurately, change the code or not as you see fit AND comment the bejesus out of it.
in reply to Should I leave behind beautiful code or readable code?
My own preference is toward simpler to understand rather than 'elegant' code - mostly because I'm only a casual programmer. Still, with sufficient comments (and a couple of reference books) I've always been able to understand what's going on in a piece of code. You can be as elegant / beautiful / complex / obtuse as you want to be IF you have sufficient comments in your code to make clear what you're doing.