I think one reason for the rise of the Christian religion was in reaction to the Roman conqueror and the mindset of brutality. The idea of placing value on what I would usually attribute to the feminine side of our race. Many of the other ideas of God are similar to hero worship and their own experience of what Royals expected of their subjects. The concept of individual freedom and value of an individual life had not as yet evolved. You can still see countries with brutal dictators and their cheapening of their subjects. We are in a new era in which many human rights are taken for granted and so the old idea of a perfect creator and Lord and master are out of tune. I think we need a religion that recognizes the hole in the doughnut so to speak about our knowledge of creation and build upon what we do know.
IMHO, sorta, but not exactly. Actually, while some of the things in it ARE a reaction to the Romans, in some ways it was quite the opposite.
For a start, Christianity did NOT value individual freedom at all. On the contrary, Paul urges slaves to obey their masters, and even returns one slave to his master.
And according to Acts (which is probably a novel, but its inclusion kinda shows what the church wanted to emphasize) Paul can make a point of not stopping in a town where he had a church, stopping in the next town, and summoning the church elders to move their ass to him and report. The church very soon emphasized a rigid church structure, and doing what you're told by your superiors.
And in other ways it's a reaction AGAINST new freedoms that were slowly becoming the norm in the Roman Empire. E.g., the pastorals and generally the early church clearly try to put the women in their place, contrary to the trend in the Roman Empire where women were getting gradually a bit more free. E.g., Paul rants against the relative sexual freedom in Rome in his epistle to the Romans.
Seems to me more like a rise of the ancient conservative religious right, than something that was about defending people's rights.
Also, it's not really unique. There was a whole trend in the Mediterranean towards:
- syncretism: combining elements of some foreign religion with Hellenic elements. Especially in the form of mystery cults (which Paul's Christianity might have been too) there were dozens popping all over the place.
- monotheism, or at the very least henotheism: the vast majority of those new cults were about a single god, not about a pantheon
- personal salvation: unlike the very old gods which were more about protecting and helping the whole community, now religion is getting to be specifically about YOU and YOUR getting eternal life
- opt-in: religion generally used to be more about the community, and therefore you didn't really have a choice not to participate. At the very least you were supposed to nod through, so to speak, and not offend the others. Now religions become more like something you have to explicitly join
- pseudo-family: religions start to take family structures and pretend they're your new brothers in <insert god>
And stuff like that.
Christianity is just one of many that jumped on that bandwagon, not something unique and different. Granted, it did hit a better mix, among other things by getting more popular among slaves and therefore then freedmen, but it's not something unique in any of those aspects, and definitely not in the aspect of being about personal salvation.