Back in the 1970s, Iran Air was a top level airline with a safety record comparable to QANTAS and excellent inflight service. Even with the sanctions in place for nearly forty years they still managed to keep going.
With the country opening up and the large numbers of Iranians abroad there is fantastic potential for the airline, especially with its location being ideal for one stop connections.
I doubt alcohol will be served and women will need to cover up in Tehran so there are limitations that the other Middle East three don't have, but the possibilities are immense.