By nature the church is to be an organic and charismatic community so if we build church in such a way that it becomes an institutional organisation then I think we are beginning to violate principles (There are a lot of terms there that need unpacking but the general point is valid). Given the radical changes in the new covenant, such as the priesthood of all believers, any development which creates a divide between supposed clergy and laity, with vestments, titles etc. is a violation of principles. As is the development of hierarchical leadership, or the politicisation of the church if it gets embroiled with State power, as it first did under the emperor Constantine.
In contrast, there are ways of ordering local church communities and their leadership for which the New Testament practice is instructive but not prescriptive, partly because of its cultural location. So exactly what we call leaders is not paramount. What are called elders in the NT provide pastoral leadership. But there are other kinds of leadership and the diverse gifting/perspectives they bring - and Ephesians 4 is vitally important here - are needed to equip the church. Exactly how they work within and toward the churches is not prescribed. The idea of an apostle being 'in charge' of the churches and 'over' the elders in their churches in perpetuity is not prescribed and cannot be justified from the NT: it was much more a case of apostles and elders working in partnership that seems to be the pattern, only requiring a more authoritative approach when things were going wrong. This will be worth exploring more.
Some worry that such a flexible or loose approach is too vague, but trying to replicate early church, first century practices is much more problematic. And is a faulty way of understanding biblical revelation. With on-going dialogue between Christians, and openness to the Holy Spirit to lead us, this approach of developing patterns without violating principles is a good and valid one.