Here's an idea for a little investigation you could do.
Last time I visited Sofia, the taxi arrangements at the new airport terminal were even more chaotic than at the previous terminal.
This is a really bad welcome for first-time visitors to your lovely country - because arriving travellers are greeted by rogue taxi drivers touting for business in the arrivals hall, and then outside there is no proper system of a queue of taxis waiting for customers - of which there are many.
Also, it is very hard for a first-time visitor to know which are "legitimate" taxi drivers, with fixed fares, and which ones are over-priced.
Why not send along a reporter pretending to be a non-Bulgarian speaking guest, and see how he or she is ripped off - then report it?
Best wishes,
Joe Hackett