I would expect that once the new person has their feet under the desk, Walsh will be gone within Eighteen months or less. If there are any more unpopular changes to BA's operations that need to be made (for example outsourcing, cost cutting) then Walsh will be urged by the Board to make them now. His successor will then arrive, all sweetness and light, as part of the "healing" process.
....At least that's the way I'd play it at Board level. Nobody is going to take that job unless they have an unspoken fast track to Walsh's desk, but even then with the existing Board and Chairman, I'm not sure it's a "do-able" job.
I think it also demonstrates rather neatly why senior executives get paid very high salaries. Cleaning up BA's image and product is going to be a very difficult and probably thankless task, with an uncertain outcome. Anyone embarking on such a perilous voyage would be entitled in my opinion to demand a very high, price and a guaranteed financial result for themselves no matter what the outcome.....ie: Golden Handcuffs and a Golden parachute.