gilded, Christ was not the first 'nice guy'. Plenty of people have come and gone and done great things. It's just Christ proclaimed to be the son of God at the same time and was executed for this blasphemy. Following on from this a bunch of his close friends spread his name around and started a splinter religion in his name that took off.
There is no reason another 'nice guy' couldn't come along and proclaim something similar and the Jewish people accept him/her as a savior and true son of god and in 2000 years our descendants can argue over his merits.
The bible and religion are great stories and it's easy to understand why people would place faith in these stories as they have no other way to explain what goes on around them.
Unfortunately for religion, humanity is developing faster and smarter than ever before and they are becoming obsolete.
Religion has served humanity in a lot of positive ways as well as negatives, it has helped to teach forgiveness and raised the bar on some moral values. Something will be required to hold that moral bar up and raise it even further in the post-religion era that we are now on the cusp of.
This comes from everyone and anyone. Regular people that teach equal opportunity, rights and liberties for genders, sexualities, races etc. People from the civil rights movement, feminist movement etc. These are the modern day Jesus's, they just don't need to proclaim to be the son of god to be heard these days.