All bmi golds are now golds for life... of the programme as no ones status is being downgraded at the end of their membership year.
Unfortunately when a scheme closes then there's nothing you can do.
BA didn't have to give anyone anything, they understood that it was good business to match status and allow us to move our miles over. Unfortunately they don't have a lifetime gold in their scheme so they couldn't match any more in that tier.
If enough lifetime golds are unhappy then they might offer something extra as a surprise gift but there's been no evidence of that happening and if they do then it's certainly more than they have to do.
Just look at it in a more positive light. bmi were performing very poor financially, Lufthansa didn't seem to have the will to turn them around and make them viable. Virgin weren't putting their money where their mouth is and even if Virgin had taken over and given all lifetime golds lifetime status in their scheme they don't have the route network of BA or the alliance to fill the gaps. So if BA hadn't taken over then bmi may have been wound up and you'd have ended up with nothing.
I'm not totally pleased with the way BA have handled this but the way they've handled it is better than most expected and as BA Silver is similar in benefits to *G then a lot of people have done quite well out of this.