Interesting thread...
Initial thoughts:
1. "We" don't all require it. Most mainline denominations in the states will require an MDiv in order to be ordained. However, you can still minister in a church without this degree... and sometime slip by the radar and even "pastor" a denominational church without one. Also, many of the new church planting movements do not require degrees for applicants to be pastors. I'm thinking specifically of
Acts 29 which is throughly reformed and has a rigorous application and evaluation process... however, no degree is required... just sound theology and proven calling to plant churches.
2. I'm not sure you're going to find the seminary model in scripture. The best seminary is seen in Jesus and the 12... our seminaries aren't quite set up like that... but maybe something to shoot for?
Along with this, I don't think it discounts the benefit or need for seminary if we don't find it in scripture. I often think of the analogy of a surgeon. You wouldn't want someone to cut open your chest and operate on you who has not been trained... Yet, we are called to be surgeons of men's souls... I think I want to learn how to yield this scalpel a little better before I kill to many people in the pew...
3. Here again... "ordination" is interesting. Is this simply the "setting in of elders" that Paul commends Timothy to do? Is that Ordination? Is modern day ordination biblical? Is it not God who ordains? Do we simply recognize those who are ordained? Not many answers... just some thoughts.
Short answer, I'd say it is ok when the candidate meets the biblical requirements of Eldership. The bible give no other requirement to lead the church.
4. YES.
Those are my thoughts... I too would be interested to read a little more on the history if anyone has a recommendation.