I am an amateur historian and my undergraduate thesis focused on slavery around the classical world, naturally, Spartacus came up. I am by no means an expert on Spartacus, Rome, or the Slave Wars in general and what I am saying is not definitive. I'd also love to reccomend Brent D. Shaw's collection of primary and secondary sources, Spartacus and the Slave Wars (It is small, concise, cheap, and an excellent collection).

First, I'd just like to note that they aren't really sure what style of gladiator he was or if he was even from Thrace. There seems to be some confusion because Thracian (Thraex) while a consortium of peoples north of Greece, was also a fighting style in gladiatorial combat (most notable differences from the Murmillo being the much smaller shield, addition of greaves, I'm sure others can add more that elude me).

Unfortunately, I don't really think we will ever really know the true Spartacus. The histories were written by the Romans who, as you may guess, have a complicated history with the man. And, as tends to be the course with legendary figures, the idealization often eclipses the actual person. The commonly spun narrative that Spartacus was some grandiose patron of liberty fighting against tyrannical Rome for the freedom of all subject peoples is unlikely. The ancient mind would likely have no conception of universal emancipation, slaveless societies, etc. Spartacus, like the other great slave leaders of the Sicilian Wars, was most likely rebelling against his (and his follower's) own immediate conditions and was not on some idealistic warpath to free all men.

Though, some of his actions (if told reliably, big if) reveal a little bit about the man. One such example being that on the day of his final battle with Rome (one that he would, as you likely know, lose) he allegedly cut down his horse in front of his men saying that (I am paraphrasing) if they won, he wouldn't need it (for the Roman camps had horses ripe for the taking) and if they lost, he also wouldn't need it for he had no intention of riding away. Pair this obvious charisma with his stunning military successes and it is no wonder he is such a focal point of history and his legacy is still going strong.

The most important thing about Spartacus, to me at least, is what he reveals about Roman society. On one level, Spartacus disgusted the Roman elite who were ashamed that a slave (i.e. generally a prisoner of war, defeated) could efficiently route entire consular armies (not just local garrisons and militias) on their home turf. The Romans were so spiteful of the whole affair that when his war ended (the sources disagree on the specifics of his death), the Appian Way was lined with crucified fugitive slaves. It was an embarrassment to Romans to have to fight slaves and that seems to be true all across the ancient world. To give you an idea, Herodotus, talking about a slave army, said all that needed to be done to route them was bring whips.

However, in later histories (Florus in particular), while you still have sentiments like:

“He [Spartacus] launched attacks on full consular armies and obliterated the army of Lentulus in the Apennine mountains and the army camp of Gaius Crassus near Mutina. Elated by these victories, he actually considered- which is shamefully enough for us-an attack on the city of Rome itself.”

There also seems to be a begrudging respect awarded to the man, likely by his military prowess alone:

“When the slaves had been defeated and driven from the field of battle by Crassus, the enemy (it shames me actually to call them this) took refuge in the remotest parts of Italy… As was appropriate for men commanded by a gladiator, they fought to the very end with no release from their fate. Spartacus himself died fighting bravely at the front his men, just like an imperator.”

Note: An imperator (where we get the word emperor) was a title awarded to victorious and successful generals of the Republic. It was a temporary position and often featured a relatively brief (usually a day or so) celebration where the general was allowed to take some credit and revel in his glory.

A common theme of Rome is revealed in the differences and similarities of this passage, Rome admired (and despised) her enemies. Rome's foes, at least in the days of the Republic, made Rome Rome. Men like Mithridates, Hannibal, and even Spartacus pushed Rome to its breaking point and, in the crucible of war, Rome gained a stronger civic identity, sense of purpose, and more prominent position in the Mediterranean.