Yes everyone should have it easy. But if the change to make things easier comes too late for you, you wouldn't begrudge the people who benefit from that change right?
I wouldn't. If the rules changed tomorrow, I would be glad of it, though probably cross with fate for not changing them until after I'd arrived. But I wouldn't blame the people who benefitted from the change.
That isn't the issue here, though. The issue is a couple who seem to think that they shouldn't have to follow the rules that everyone else is bound by. As garry said, the no-switching rule isn't going to change, and this couple clearly didn't do the proper research if they thought that getting a CoA was the best path for them to take. It's too bad that things turned out the way they did, but the couple does bear some responsibility for this outcome. Not only was their research inadequate, but their time frame wasn't very realistic.
Perhaps the Home Office should have some discretion with the under-21 rule in cases where there is clearly no forced marriage. But this couple doesn't make a very good test case for that since what they tried to do was outside the rules even if the under-21 thing wasn't a factor.