There was a series of rather poorly written novels dealing with an alternate republic. If I recall correctly the first novel was called Hannibal's Children, by a John Maddox.
In it, Hannibal forces the republic into exile, and all the Romans head north and try to start over in Noricum. Eventually they are something of a footnote to history and then one day decide to return to Rome and take their revenge or what have you.
The writing makes the Romans look infallible, and generally the culture of Rome as portrayed in the book makes me think of sword and sandal epics where everyone is either Massala (Boyd) or Lucius Verus (also Boyd). A little campy to say the least.
However, the republic as it is in this book, because it was kind of "reset", if you will, is a little bit stronger than as was in our time. That is to say, what's most uncanny valley about this novel is how the republic in PRACTICE is working according to its theoretical principles....which we all know broke down under the weight of greed etc. For instance, power politics in the forum pit new men against old families, Romans vs. Norici (?) recently adopted into the fold....yet the moment there is an external enemy....poof. Everyone closes ranks. Not for nothing but, I don't buy it.
Anyway by the second book they are already back on the road to empire, kicking everyone's ass, except a few years later than happened in OTL. So, I'm not really sure what's great about the story. There you have it.
Cheers.