I'm reminded, inexorably, of a filksong that a friend named Jill Stone wrote many long years ago.
Sung to "What a Friend We have in Jesus"
What a fiend we have in Davros
Worst mad scientist we've met,
Fragile, yet we cannot kill him
At least no one's managed yet.
As a fiend he has no equal,
Kills the whole darn universe!
But he's wonderful for sequels,
Daleks, only, would be worse.

There was a second verse, but I haven't been able to find the zine that it got printed in...