Most Bible translations indicate that there are textual issues with John 7:53-8:11, which is the story of the woman caught in adultery who was brought to Jesus for judgment. Some are suggesting that this passage should not just be noted to have difficulty but removed from the text entirely.
What are the difficulties with this text and when should textual questions lead to the actual removal of a phrase or passage from the Bible?
With regard to John 7:53-8:11, the story of the woman taken in adultery, the late great Harvard NT scholar George W. MacRae S.J. sums up what seems to be scholarly opinion when he writes: “…The moving story of the woman taken in adultery, which has for centuries appeared as John 7:53 to 8:11, is not found in the oldest and best manuscripts of the Gospel and is certainly not an original part of it” (George W. MacRae, Invitation to John [Garden City, NY: Doubleday/Image Books, 1978], p. 18, cf. pp. 108f.).
As one commentary notes, the Revised Standard Version (so excoriated by fundamentalists) prints the story not as part of the text but in a footnote. – The question arises, How could “the scribes and the Pharisees” (8:3) present this situation as a “test” (8:6) or trap for Jesus? Here too George MacRae gives us a persuasive answer: “We have to suppose something like the following. The Jewish court has legally convicted the woman and sentenced her to death according to the Mosaic Law (see Lev. 20:10). But the Roman authorities in Palestine do not permit the Jews to exercise capital punishment. If Jesus advises against execution, he is in conflict with the [Mosaic] Law. If he recommends it, he is in trouble with the Romans. – Jesus skillfully evades the trap by refusing to answer the question” (op. cit., pp. 108f.).
So you see that it is not a question of modern liberal translators inserting passages that don’t belong in the Bible. On the contrary, these are passages which have been disputed for nearly two millennia. I would say that the most justice is done to the text neither by omitting them without commentary nor by printing without commentary as part of the text, but by printing them with brief comments indicating scholarly doubts about their authenticity.
"Textual difficulty" does not warrant removal of specific pericopes. While it is true that there was a good bit of jockeying over the authentic canon of scripture in the early centuries of the Church, through various councils and documents of bishops, what is really more important for our contemporary understanding of Biblical text is that at least the New Testament has remained the fixed Christian scripture for some 1500 years. Catholic and Orthocox scholars would take the point a step further: the Biblical canon as a whole has remained fixed for the Church for that same period of time.
With the Protestant reformation there arose questions about "textual difficulty" related to the origins of Biblical materials-- specifically, the seven deuterocanonical books that were written later than the Septuagint version of the Old Testament. On the Protestant side, the judgment was made that these later additions did not hold the authority of those texts used by ancient Israel, and were rejected from the canon. The Catholic and Orthodox positions were that these texts were part of Christian scriptures-- that is, used as sacred texts by churches such that by the fifth century (or so) there was no dispute about the canonization of these texts.
Regardless of which position one holds, what is undeniable is that the canon of the New Testament has never been the object of the kind of historical scrutiny that would seek the removal of entire pericopes such as John 7:53-8:11. Even the Freer Logion (Mark 16), which may be an ending written several centuries after the text of Mark's gospel, was included in many post-16th century versions of the Bible (e.g. the Vulgate, the King James Version), in part because that ending shaped Christian imagination of the resurrection story.
In short, "textual difficulty" does not warrant significant alteration of New Testament texts. It should help shape Biblical criticism, but not significantly alter those larger works which have shaped Christian imagination.
In response to the second part of the question—the removal of the text altogether. We are dealing with a canon, which means items included are deemed authoritative and that the content to be included has been determined by an authoritative group. The process for removing a section/chapter/periscope would necessitate agreement by some type of authoritative council. These things do not happen quickly or easily. If a Bible translation committee were to make such a decision on their own they would be taking action independent of the larger faith community. Such an act could, and probably would, be dismissed as inappropriate and the project, therefore, negated by many.
John 7:53-8.11 is indeed removed from the traditional text because of its absence in the older manuscripts. Why it is kept in the footnotes is that it is known to be there in the King James Version, and people will wonder why it is not there. There are also scholars who feel that it genuinely goes back to Jesus even if it isn't in the canonical texts.