stut, thank you for your detailed reply.
You've had better luck in Romania than I have. Bucharest was dire, stray dogs, buildings in various states of decay, etc. I had read good things about Transylvania and was looking forward to spending a few days in the region. My first (and last) experience with Romanian trains was a train ride from Bucharest to Brasov. The condition of the train was poor. The train left Bucharest late, that really wasn't much of a problem. The journey took double the time it was supposed to as the train stopped in the middle of nowhere several times. One of the stops was a little over an hour. All announcements were in Romanian, so I'm not 100% sure what the reason was for these stops. The long train journey ended at some unearthly hour in Brasov.
I had coined a draft itinerary for the Balkans last year but the trip didn't materialize. You've given me some good ideas, I can either chip away at some destinations in the Balkans or leave the trip for when I can travel for longer.
As for Malta, the more I look at this, the less it appeals for a week long stay.
Fortunately, I don't need miles to requalify for status so I'm not restricted to BA's network.
Will continue to explore other options.