I think Balbo is very good choice for the next duce since he can help slow down fracture between Democratic and Fascist that is greatly needed currently.
I expect Balbo will have a number of tactical successes; and get a lot done by force of personal charisma too. But I think his reign will see the Fascist system enter its irreversible strategic decline. A big part being endless wars in places like East Africa, the minority rule states, Latin America, and Greece. Loss of the Red Menace, and Italians that increasingly question the system even if they still hold Mussolini in high regard. Possibly the Church will get a Vatican 2 equivalent and increasingly be a problem. Some allies might abandon them as well while others become major liabilities doing more harm than good.
I think Balbo will die in power, but by the time that happens a lot of disillusionment will have built up and discontent with the status quo. And with Balbo gone people will start demand change inside and outside the RA more than ever before with a new head of the regime. There will probably be a third Duce, buy they will fall inside ten years, either trying to reform the system and losing control of the process and their seat, or a hardiner who gets overthrown trying to hold the line would be my guess.