Here at MT, we think this sounds eminently sensible. Although we’re not entirely convinced by the succession argument; experience suggests that ‘planned succession’ is almost as much of an oxymoron as ‘military intelligence’ because however carefully you prepare you can’t predict the future, and things just have a habit of going pear-shaped on you.
But anything which tempers the human instinct to strive for control, and having gained it, to keep it - the ‘Will to power’ as Nietzsche had it - is probably a good thing. And if nothing else, fixed-term contracts would at least provide organisations with a much less disruptive ‘last resort’ way of getting rid of a toxic or out-of-control boss than they have at present. An upside which probably looks pretty appealing to the chairs of a number of the world’s more troubled large financial institutions right now.