Duncan Fletcher won't be in the job for ever ... maybe not after the next World Cup. Who would you like to see in his place? (It doesn't matter if they're doing something else now, eg writer, commentator, just assume he'll be available).
Involved in the setup maybe, but not as manager. He would be a disaster. From what I've seen of Botham he comes across as extremely arrogant, opinionated and intolerant. Great player but frankly, not a very nice person. You may as well put Alan Sugar in charge.