Alternate history - What if? Carthage, Roman, and Battle of the Metaurus

[AntiochusIII]

Carthage for example had some rather nasty rites, like sacrificing children in fire to the gods and crucify generals who lost if they were belived to have gained the anger of the gods.

That is disputed. The evidences are unclear -- those cremated babies could either be sacrifice, as is generally believed, or they could merely be a religious practice dealing with the remains of babies that died by other means, after all the ancient world's mortality rate for young children were extremely high -- and the only written records of such practice came from the Romans. They had every intention of vilifying their mortal foes.

and Colosseum won't exist

Rome wasn't the only culture that engages in barbaric pitfighting.