A couple of things:
1) The whole "cult" discussion. By definition a cult is:
1 : formal religious veneration 2 : a system of religious beliefs and ritual; also : its body of adherents 3 : a religion regarded as unorthodox or spurious; also : its body of adherents 4 : a system for the cure of disease based on dogma set forth by its promulgator <health cults> 5a : great devotion to a person, idea, object, movement, or work (as a film or book); especially : such devotion regarded as a literary or intellectual fad 5b : the object of such devotion 5c : a usually small group of people characterized by such devotion
So, if you were to go with the current structure of Christianity -- there being these denominations and organized structures -- then yes, Christianity would be considered a "cult." But there are many things that would be considered "cults." Fraternities and sororities would be considered cults. A "cult" typically has a negative connotation, we made it that. A cult does not have to be negative.
I will argue, that Jesus never set out for Christianity to be operated like it is currently. There should be no denominations. There should be no "sacred buildings." There should be no designated "priests" (which does include pastors and other formal hierarchical authorities in the "church"). The "cult" notion would be lesser if this were the case. A "Christian" by definition is "Christ-like." One's life would imitate that of Jesus.
That leads me to part:
2) Yes, all you truly have to do is proclaim Jesus Christ as your Lord and Savior. But, we know with that proclamation that there are changes. This goes along with being "Christ-like." This is the thing that most "Christians" have a hard time doing. Those changes would be "love God, love others" (just to make it short and sweet). One would strive to be closer to God, just like any other relationship or friendship. You seek to grow closer to your friend. You love your friend. You talk and listen to your friend. Friendships and relationships are two-way streets, not just one-way.
Sorry I was gone...I know everyone missed me in this discussion.