I think what Cimbrio wrote is true, the monarchy probably won't be restored in Bulgaria - although there's an off-chance that it could be, given the right circumstances.
However, when I was in Bulgaria I noticed that Simeon's father, Tsar Boris III, was still regarded with fondness, even with a great deal of nostalgia. Taxi drivers liked to point out to us Boris' Garden and the Tsar's Highway (near Shipka, where, we were informed, Boris liked to race cars). They (and all the other Bulgarians I met, even on the Left) also invariably referred to Simeon as "The Tsar." Not Simeon Saksborgotski or "the prime minister," but - "The Tsar."
And, as I was informed by a reliable source, this is also the case with all of his ministers in the government: Simeon is not only "The Tsar," they even address him as "Your Majesty." Simeon is accorded this degree of respect partly because of his own political accomplishments (such as getting Bulgaria into the European Union) but also and perhaps even more importantly because of the enduring historical legacy of his father. Boris III is still popular among Bulgarians because of his wily maneuvering during WWII, his annexation of ancestral Bulgarian lands, and the rescue of the Bulgarian Jews from Hitler's clutches (although those Jews in the annexed territories perished). His untimely death - many still believe he was poisoned by Hitler - only adds to his mystique.