First, obviously we would disagree about what an early Christian was like. Most Protestants who want to "be like the Early Christians" would deny that they believed the bread and wine became the actual body and blood of Christ. Actually, all evidence we have and all the writings of the early Christians indicate that they did, along with the New Testament record and Christ's own words. They would also reject that the Church followed a liturgical worship schedule, which it historically obviously did. So, when you wanted to "be like the early Christians", you would actually be a Catholic - obviously not what they think an early Christian was. Also, with their belief in "sola scriptura" they would have a hard time understanding how the New Testament wasn't laid in stone until 400 A.D. how the early Christians would base almost everything they did off sacred Tradition (there I said the "T" word!)
But, perhaps even more importantly, if we were to "become like the Early Christians" we would have to forsake the Church as it is today. Christ created a living body to be his Church; His Body. An organic body doesn't simply stay in a static state, unable to adapt and grow, but instead it becomes a much stronger, more well defined, larger entity growing daily and becoming more aware of truths of faith and morals. This organic, dynamic body is what the Catholic Church is, and to forsake 2000 years of growth would be ludicrous to say the least. Here, if someone was more interested, they might pursue more about the Catholic Church and doctrinal development.
I think Christ put it best when he referred to the Church (or Kingdom) as a mustard seed:
Mark 4:30-32 (RSV)
"And he said "With what can we compare the kingdom of God, or what parable shall we use for it? It is like a grain of mustard seed which when sown upon the ground, is the smallest of all the seeds on earth, yet when it is sown it grows up and becomes the greatest of all shrubs and puts forth large branches, so that the birds of the air can make nests in its shade"