His job as CEO will be to make the strategy rather than (as COO) carry out the strategy. He'll probably be okay at making the strategy as he's likely to draw heavily on his experience at ours.
seems like he's been a good servant for the club so good luck to him i say (but not too much luck).
make all your errors at united, and if a vacancy for CEO comes up at city and if you're any good as CEO, and if you've been respectful about your former employers, then maybe there'll be a conversation. i suspect you'll have fond memories.