Dan, there are two interesting concepts here as you are aware. The concept of development in the church. And the concept of expediency.
It seems to me that there was indeed some development in the early church which occurred under the direction of the Holy Spirit. Jesus did not explain every detail in his own life before leaving the earth. He left that to others who spoke with his apostolic authority.
As for expediency, it't just old fashioned common sense. The Ethiopian inquirer in the book of Acts said: "Hey, I get it. Here is water. Let me now be baptized." In today's world, he would likely be told to "go to church", get plugged into a new members class and be baptized by a pastor, months later...
As for the principle of development in the church, it's seen when the church realized: We got problems and we need to become a welfare agency for the poor. And seven were immediately chosen for this task.
When development gets out of control, the result is a massive apparatus that grows almost like the bureaucracy of our federal government. You can see this in the Catholic Church which at one time had dozens and dozens of church "officers". They not only had deacons but arch-deacons.
As for places to meet, when the Israelites were in captivity, the naturally formed groups to meet in. And called these synagogues, which continued on and on. And were made use of by Christ and the apostles. My point is that they were not commanded to organize synagogues. It was just a natural impulse and worked fine in many instances just as house churches also do today.
It's always good to ask: How did we get from here to here?