J.C. Wenger said it is a “queer notion that because the Anabaptists were vigorous in their demands for a life of earnest Christian discipleship, they were therefore unclear on grace and justification.” In the same context he references Menno Simons, who set forth a clear doctrine of justification by faith, one compatible with Reformed doctrine. Menno does, however, constantly emphasize that any true profession of faith with have with it works which confirm the claim. As we will see from the sampling of Anabaptist writers, justification by faith alone was certainly a part of their theology.

This is good, I largely agree with your argument.
There is a good quote from Calvin illustrating what Wenger said – that the Reformers did not teach that obedience is unnecessary or that you can be justified without also being sanctified. I’ll post it below.
In addition to the emphasis that Anabaptists put on repentance and reformation of life, beyond justification, I think the main difference, the core of the difference, between the Anabaptists and the Reformers lay in ecclesiology – their doctrine of the church – and their views on the relationship between church & state and between the church and the rest of society. This is why there was a noticeable difference between the lives of the Anabaptists and those in the Reformed state churches. There are modern Anabaptists who attribute that difference to soteriology, and who equate modern “free grace” theology (that you can sin all you want to after salvation and still be saved) with the views of the Reformers, but my understanding is that’s not true; “perseverance of the saints” is not Biblical and may have a tendency to be misunderstood among the common people as modern “once saved always saved”, but the Reformers did not teach OSAS in that sense. The main difference can be seen in the Puritans; when they went to America, the first generation tried to establish a godly society that encompassed all of society, and at first, they were fairly successful. But the following generations did not maintain the original zeal and were not born again, and they ended up compromising, with the Half-way Covenant, to try to maintain their society.
So in the Reformers’ theology, their theology of the church and church/state relations conflicted with their theology of salvation, resulting in unregenerate people in their churches and a lack of reformation of life in spite of their insistence that sanctification and obedience are necessary. And the Anabaptists pointed that out.
We can also see this in modern churches that practice open communion and have no church membership, thus no adequate means of church discipline. It’s a different error than the Reformers (these are usually Baptists or evangelicals who agree with freedom of religion), yet a similar result, with the church not being different or set apart from society in its holiness and manner of living. (Since these people usually believe in OSAS we tend to lump them under the term “Calvinist” which isn’t actually accurate).
Here’s the quote from Calvin:
“We dream not of a faith which is devoid of good works, nor of a justification which can exist without them: the only difference is, that while we acknowledge that faith and works are necessarily connected, we, however, place justification in faith, not in works. How this is done is easily explained, if we turn to Christ only, to whom our faith is directed and from whom it derives all its power. Why, then, are we justified by faith? Because by faith we apprehend the righteousness of Christ, which alone reconciles us to God. This faith, however, you cannot apprehend without at the same time apprehending sanctification; for Christ “is made unto us wisdom, and righteousness, and sanctification, and redemption,” (1 Cor. 1:30). Christ, therefore, justifies no man without also sanctifying him. These blessings are conjoined by a perpetual and inseparable tie. Those whom he enlightens by his wisdom he redeems; whom he redeems he justifies; whom he justifies he sanctifies. But as the question relates only to justification and sanctification, to them let us confine ourselves. Though we distinguish between them, they are both inseparably comprehended in Christ. Would ye then obtain justification in Christ? You must previously possess Christ. But you cannot possess him without being made a partaker of his sanctification: for Christ cannot be divided. Since the Lord, therefore, does not grant us the enjoyment of these blessings without bestowing himself, he bestows both at once but never the one without the other. Thus it appears how true it is that we are justified not without, and yet not by works, since in the participation of Christ, by which we are justified, is contained not less sanctification than justification.”
Good thoughts. I agree with your perspective that the main difference between the Anabaptists and the Reformers was their ecclesiology. That’s not to say there weren’t differences in other areas, but the key difference was ecclesiological (pure church, believer’s baptism, church free from state control).
The parallel with modern churches is interesting. In both cases (16th and 21st century) the lack of a disciplined church distracts from its purpose and dilutes its witness.