If you can pass the rating? Really? Are you trying to somehow suggest that BA's training is so inadequate that professional, experienced pilots regularly fail to convert on to a different type? Spare us the nonsense please. If you've jumped through all the hoops, it's simply not fair to 'wipe the slate clean' and delete the entire hold pool after an arbitrary period of time. It's not the candidates fault BMI got took over and his job offer got delayed.
The people that passed the selection should have had a job offer when there was place for them. Whether it took one, four or five years. That would have been only respectful to people that took the time, effort and energy to go through all that stuff in the first place. It would have only been right to leave it up to the candidate to make the decision whether, after all that time, they should accept a job offer or not.