It doesn't do to say that heresy produces the development of doctrine, because that annoys the theologians. But it is true to say that as a matter of history the development of doctrine has been largely a reaction of the Church's part to the attacks of heresy.And my two bits: my experience of "Catholic sacramental sensitivity" (G. Bailie) always has found theme and substantiation in doctrine. Doctrine is not something to jibe against the goad; doctrine is the Word formulating at a distance at which we humans can formulate both faith and reason. No reason for resentment here. Move along.
The defined doctrines ... are guaranteed by a promise of Divine guidance; whatever else is or is not true, these must be true. Therefore, you must resign your conclusions, you must submit your reasoning processes to the refutation of this higher certainty.