There are a fairly standard set of objections that are used against Christianity. Just to name a few: Christianity is notoriously homophobic, has outdated views on sexuality and reproduction, has a long history of wanton murder, horrendously intolerant of other points of view, and insistent that people were born as broken, wicked, evil people, who deserve to burn forever unless they bow to Jesus.
All of these are blatant problems that typically drive people away from Christianity. Even many Christians have adopted the "New Covenant" doctrine to allow them to casually discard the Old Testament whenever it becomes inconvenient, simply by claiming that Jesus changed the verse in question. This argument typically doesn't hold up when arguing against non-christians, as non-christians realize that the Old Testament seems to not apply, only for those verses where the Christian in question doesn't want that particular verse to apply (i.e. homosexuality is still a sin, but dietary restrictions on eating shellfish don't apply, even though they're in the same book).
Bearing this in mind, I would like this post to be a mixture of a brief history lesson, and some wishful thinking. You see, Christianity didn't have to be this way. In the early to mid second century,
Marcion of Sinope was heading up the Marcionite church, which, for a few years, was a real contender to become the dominant Christian faith.