Evangelical Anglicans are right to be suspicious of throwing everything in with Rome. While they are minorities in North America, they are a part of the vast majority worldwide. Why swim the Tiber when the Congo and Niger are perfectly good for swimming these days? Another point of concern should be the Roman method of doctrinal analysis. Dogmas such as the Immaculate Conception, Assumption and Papal Infallibility were defined as dogmas only in the last 200 years. These dogmas, which were debated for centuries, were put into full force right next to the Incarnation and Resurrection not because they were solidly backed by Scripture and Tradition (Thomas Aquinas and Anselm taught contrary to the present Immaculate Conception doctrine), but because the leaders of the contermporary church (i.e. those bishops at Vatican I) thought them appropriate. To evangelicals, allowing a church council to outweigh Scripture and Tradition smells too much like what happened at GC 2003.
Tremendous difference between a council clarifying something that is ambiguous in Scripture (after all, isn't that exactly what Nicaea did?), and a council directly and flatly contradicting the whole Christian moral tradition and choosing obedience to the zeitgeist over obedience to God.
But forget GC 2003 -- it happened at Lambeth, 1930, where the Anglican Communion discarded 2000 years of uniform Christian witness that artificial contraception was a sin, becoming the first Christian group to do so.
Then again, those of us who are Catholic believe that the Church gathered in an ecumenical council is infallibly guided by the Holy Spirit when it defines dogma. Not even Anglicans think that an ECUSA convocation is "the Church gathered in an ecumenical council".
Very different. The authentic conciliar teachings to which you refer were adopted firstly by the proper teaching office in the Church, i.e., the successors of the apostles in union with the successor of Peter. And the doctrinal definitions were based on concepts found in Tradition and were natural and organic explanations and developments within the confines of Scripture and Tradition. They are, as John Henry Newman would say, authentic development of doctrine, not reversals of the deposit of faith. The teachings of GC 2003 on same sex unions and episcopal homosexual activity have no basis in Scripture and Tradition and in fact contradict Scripture, Tradition and the constant and universal teaching of the Church based on them. It is a reversal of the teachings of the deposit of faith, not an organic development. Look to Newman!