I used to have a "Bitcoin-Qt Wallet Migration Tool".  I finished it and integrated it about a month before the Bitcoin-Qt devs made the change.  I tried to keep the migration tool in there for users who would benefit from it, but I ended up with users complaining about how Armory was broken because it claimed that they could migrate their wallet, but it never worked.  It was much simpler and more-pleasant to just remove it altogether than to try to explain the complex situations in which it will work, and that situation is actually quite rare by now.