>>So, should we get back to the practices of the ancient church? If this passage from Justin provides the model, I’m all for it.<<
Amen and Amen! And those who are truly called out by God (the ekklesia) will do just that as the "churches" we have today all drift farther and farther from the truth of scripture.
You are going to find out that the nearest assembly evincing likeness to the New Testament Church(es) is that following the pattern of brethren reinstituted by John Nelson Darby and his Christian friends and titled, after the location in which they first assembled, as
Plymouth brethren (small "b" in brethren), non-denominational immersionist assemblies meeting now across the globe. These would almost exactly have been such as those described in the above article by Justin Martyr, and conforming to the local assemblies as seen in the New Testament. The church polity is government usually by a plurality of men spiritually mature enough to be defined as "elders."
Next to it would be the independent fundamental "baptist" assemblies that feature a local pastor as the schooled elder/teacher, with deacons assisting the orderly conduct of the organization. Except for the distinctive characteristic of one sole ruling pastor, they also would fit the description of a New Testament church, as contrasted to any denominational church arising out of trying to mend the misbehaviors of the Romanists four hundred years ago. None of these Protestant denominations can meet the Justin Martyr test, IMHO.