Anthony Le Donne recently posted a poll, asking "Was Bultmann's impact generally positive or negative?" Looking at the results I'm glad to see that (at the time of writing this post) 73% of respondents have selected the correct answer, namely "generally positive." Indeed, the only reason that Bultmann's legacy is ambiguous is because Bultmann's readers, and one suspects Bultmann himself, too frequently fail to understand the nature of his genius. And he was a genius, about that there can be no doubt. Of what did his genius consist?
Let us recall Lonergan's division of theology into eight functional specialties, grouped into two "phases": the first phase includes research (i.e. text criticism and the like), interpretation (i.e. exegesis), history, and dialectic; the second includes foundations, doctrines, systematics, and communications. I think we can all agree that Bultmann's genius did not consist in research, interpretation, or history. The closest he came to research was his work in form criticism, which it is probably safe to say no one really practices anymore, not at least in anything resembling the Bultmannian practices. This is not because we've moved past Bultmann but because we have come to realize that his thinking here was a dead end. Regarding interpretation and history, very few of his specific exegetical or historical arguments have stood the test of time, and indeed some read today as outright howlers. He is often not only wrong but not even wrong: proceeding on such questionable bases that one can only respond by a incredulous shake of the head. Frequently he sees contradiction where none exists (for the life of me I cannot imagine how the doctrine of Jesus' preexistence contradicts the doctrine of the virgin birth), and as Chris Keith has been arguing for some time his understanding of form criticism has being wracking havoc in historical Jesus studies for the better part of a century.
Regarding dialectic, which is concerned with what something similar to what Newman would call "doctrinal development," consider the emphasis Bultmann put upon the "gnostic redeemer-myth" as a background for the New Testament, when in fact it is increasingly clear that gnosticism in its developed forms post-dates the New Testament and that the "redeemer-myth," if it was ever actually a thing, probably constituted a particular range of second-century Christian developments from first-century Christian doctrine. In fairness to Bultmann our better knowledge of these matters is derived to a large extent from data unavailable until the tail end of his career (i.e. the discoveries at Nag Hammadi and Qumran); one suspects that he might have written something quite different had he had that material available. Yet even on the data available to him there was in fact little reason to think that Gnosticism was a thing in the New Testament period.
That all said, it was precisely in dialectic that Bultmann's genius resides. Ben Meyer argues that central to doctrinal development is the work of translation. When Christianity moved from a predominantly Jewish to predominantly Gentile world it had to translate its central convictions from idiom to idiom. It has been continuing to do so for two millennia. Bultmann's genius was that more clearly than almost theologian of the twentieth-century he grasped that the work of translation continues, and that in fact if academic biblical studies is to make any contribution to the life of the Church or the churches it is via undertaking the work of aiding in the task of translating the Christian proclamation into the idioms of contemporary academia. If he hitched his horse to the Heideggerian wagon it was not because he thought Heidegger's understanding of life and the world was definitive or even superior to that of Christianity but rather because he thought it representative of the idiom du jour and thus the appropriate destination "language" for his work of translation. Really, such translation is all Bultmann means by "demythologizing."
What does that mean for our "reception" of Bultmann? It means that in fact we can reject most of his exegesis and his historiography, and that we are hardly obliged to emulate his tendency towards an existentialism that is itself now quite dated. It means simply to recognize that Bultmann's genius resided not in doing anything new but rather in doing what theologians had always done: translate the Christian proclamation from one idiom to another. The theologian most faithful to the Bultmannian legacy is the one who joins him in joining that great throng of Christian thinkers dating back to at least St. Paul.
And if you have not yet voted in Anthony's poll, go do so. And choose wisely (yes, that was a subtle reference to Indiana Jones and the Last Crusade).