When does Commodus die? If it's before 175...then it is, without a doubt, going to be Avidius Cassius, as Agricola said. Now will this prevent the third century crisis? No. But butterflies do have an effect here-Commodus may not have caused the crisis but he certainly exasperated it with his terrible management of the treasury. There's also the fact that the Romans are going to take a different route with Bohemia under a Cassius than under Commodus.
Then you have two really interesting side effects: No Severans, and, possibly, no Sassanians. The Severans of course massively expanded the army and weren't the best at managing the treasury. One can make a case that they exasperated things with their "worship the soldiers and fuck everyone else" mantra (well, Septimius and Caracalla, that is). That might have played a contributing role in the complete breakdown of discipline and loyalty that characterized the crisis.
And of course...butterflying away the Sassanians is a MASSIVE change for the eastern frontier for Rome. Heather is right when he puts them near the top of his list for the rise of the dominate, and the need to split the empire in 2.
Then you have two really interesting side effects: No Severans, and, possibly, no Sassanians. The Severans of course massively expanded the army and weren't the best at managing the treasury. One can make a case that they exasperated things with their "worship the soldiers and fuck everyone else" mantra (well, Septimius and Caracalla, that is). That might have played a contributing role in the complete breakdown of discipline and loyalty that characterized the crisis.
And of course...butterflying away the Sassanians is a MASSIVE change for the eastern frontier for Rome. Heather is right when he puts them near the top of his list for the rise of the dominate, and the need to split the empire in 2.