Was Illich ever disciplined for his views? And what was the source of tension between him and the "Vatican"? The fact that he was so opposed to the political status quo? That he did not accept what certain members of the Curia were saying about development? Was he critical of the Church because he thought there was too much acceptance of what the industrialists and globalists, the moneyed elites, were putting forth as necessary for development?
Was he ever corrected for what he believed and said about contraception as being necessary, for the sake of sustainability? With regards to abortion, he disagrees with those who claim that fetuses are human. That does not mean he is necessarily wrong, since this is not a part of Sacred Tradition (as far as I can ascertain). But he also advocates the use of abortion as a form of contraception and population control. This is problematic.
Illich seems to believe that the Church has become corrupted by power, and is more concerned with maintaining power than with the practice of charity and the spreading of the Gospel. That is what I gather from the publisher's introduction to The Rivers North of the Future: The Testament of Ivan Illich, as told to David Cayley, foreword by Charles Taylor, Toronto: Anansi Press, 2004. 252 pp. If Illich is such a radical with respect to his views of the Church, why is Charles Taylor writing the foreword? The book is available at Google Books, so it's on my reading list.
From the discussion of Illich's life in the foreward and introduction we are told that Illich was critical of a rule-bound Christianity, which he believed to be a corrupted version. He was a radical in the sense that he called for a return to the early Church, one that was purified of the worldly institutional Church that is too entangled with politics and too grasping for power (6-9). (Another version of the thesis of the post-Constantinian Church being a corruption?)
Illich makes clear his objections to (privileged) people doing service work in a foreign country in To Hell with Good Intentions, including missionaries. Would he make the same criticisms of Catholic missionaries who are there to evangelize first, and to help bring clean water, etc. second?
Given his relationship with the Church and his [problematic] views, should he be trusted as an credible authority on [economic/industrial] development and its consequences? I think so, since these are not matters of Faith, but that doesn't mean he shouldn't be read with a critical mind.
Richard Wall, A Turbulent Priest in the Global Village: Ivan Illich, 1926–2002
Louis Bouyer, in The Church of God, talks about the two models of the Church (and of evangelization) - the Church of believers and the Church of numbers (22-25). He sees the transition between the former to the latter taking place after the Peace of Constantine, when Christianity became "socially acceptable" and soon was socially required.
Only those societies in which members have freely chosen to become Christian can be called Christian; those in which coercion is employed are problematic. But how is a Christian ruler to govern a Christian polity? How does he deal with non-Christians? What is the proper relationship between the Church and the State? What is the nature of the Church's authority over the baptized and civil governments? Illich, Bouyer, and other theologians and Christian intellectuals offer answers to these questions. What are Christians are to do once they gain control of civil authority? Our Lord does give a clear answer within Sacred Scripture, and Christians have been attempting to discern what to do, with the help of the Holy Spirit and the teaching of the Church. Does Illich have a romantic view of the early Church?