If the term "household tables" goes back to Luther, as the OP has suggested, who in his commentary on family member duties used the term haustafel, then a modern definition could be the one included in Wikipedia's entry for the same German word:
"The proper domestic or household order in the Christian home. It implies the highly practical nature of the instructions: an individual's 'haustefel duties' are not related to abstract beliefs they are expected to hold to, but rather to specific actions they are expected to perform"
These actions, I suggest, are to be characterized by love, mutual submission, obedience, and honor. In short, "household tables" address family relationships: husband, wife, children, bondslaves and masters; and church-family relationships: elders, deacons, young and older men, young and older women, and Christian bondslaves and their believing masters.
Carolyn Osiek and David L Balch, the editors of the book Families in the NT World: Households and House Churches (in the Family, Religion and Culture Series; Louisville: Westminster/John Knox, 1997) suggest the following:
"On the whole, neither Christian nor Jewish families stood out against the wider Greco-Roman background. The cultural influence of the Greco-Roman environment was so strong that Christian and Jewish families looked quite similar to Greco-Roman families. Not until several centuries into the Christian era do distinctively Christian families begin to appear. Part of the reason is that in the early Christian centuries, Christians were quite the minority in the population; Ramsay MacMullen [prof of history and classics, Yale] estimates that perhaps 5 percent of the population was Christian, slightly more in the urban areas, but slightly less in the rural" (see http://web.campbell.edu/faculty/vandergriffk/foundations_new_testament.html).
Osiek and Balch may be correct in that it was "not until several centuries into the Christian era [until] distinctively Christian families [began] to appear." By the same token, however, the unbelieving Greco-Roman world in which Christ promised to build His church did take notice of the qualitative difference between the behavior of Christians and Christian families and their secular equivalent, and for this reason many Christians subsequently became martyrs for the faith.
The hortatory content of the "household tables" in the writings of the apostles Paul and Peter was therefore unique, with the Christian subculture in the apostles' day being countercultural in many ways, morally and ethically. Furthermore, the hortatory "oughts" of scripture were not given to the church as a pattern for ushering in heaven on earth; rather, they were given to instruct believers on how they were to "conduct [themselves] in the household of God, which is the church of the living God, the pillar and support of the truth" (1 Ti 3:15, my emphasis).
As individual believers and believing families manifested the love of Christ both within the church and in the world, they functioned as beacons of light amidst the darkness. Peter said,
"But you are A CHOSEN RACE, A royal PRIESTHOOD, A HOLY NATION, A PEOPLE FOR God's OWN POSSESSION, so that you may proclaim the excellencies of Him who has called you out of darkness into His marvelous light. . . . Keep your behavior excellent among the Gentiles, so that in the thing in which they slander you as evildoers, they may because of your good deeds, as they observe them, glorify God in the day of visitation" (1 Pe 2:9,12; emphasis--all caps--is in the NASB).
Just as Israel of old was to be
"a light to the nations . . . so that . . . [God's] salvation [might] reach to the end of the earth."(conflation of Is 42:6 and 49:6),
so also the church today, which Jesus described as "the light of the world" and "a city set on a hill," provides an example to the world around her, so that it might see our good works and glorify [our] Father in heaven (Mt 5:14-16).
I challenge anyone to identify any extant code in either the time of ancient Israel (or before) or the time of Jesus that organized and laid out "household tables" in a form that resembled even remotely those of the authors of the Old and New Testaments, including the apostles Paul and Peter. Why? Because the Bible, unlike manmade laws and regulations, was divinely inspired. No manmade code can surpass in simplicity and profundity the pattern laid out in God's word for His people.
Paul may have received as part of his education, particularly under his mentor Gemaliel, some instruction in rhetoric, but I would have to research that further. If he did have instruction in rhetoric (both the oral and written applications of its principles), his "household tables" could simply be the product of his being taught the importance of organization in the process of speech preparation and letter writing. The Roman rhetoricians, such as Cicero, called the process of organization dispositio.
Today, we take for granted the importance of organizing a speech around two or more key ideas that support a thesis, or central idea. In Paul's day, then, his thesis in this quasi-genre of haustafel was that the various roles that Christians assume in their day-to-day lives are to be informed by key Christian values of love, mutual submission, obedience, and honor, and his methodical way of going about his main points (i.e., I. Wives to Husbands; II. Husbands to Wives; III. Children to Parents; IV. Fathers to Children; V. Slaves to Masters; VI. Masters to Slaves). This pattern of organization Paul may have shared with Peter (and not vice versa, I surmise).
The family of God in general and the Christian family unit in particular, then and now, serve as exemplars to the unbelieving world. Sadly, today in America the Christian family is beginning to behave like the culture at large, with divorce, adultery, and fornication, for example, being relatively common occurrences in local churches. What a travesty for local assemblies of God's people, whom God meant to be examples of marital fidelity and sexual purity.
If only the command for husbands to "love [their] wives as Christ loved the church and gave Himself up for her" were the extent of "household tables" in the NT scriptures, that alone would be sufficient for giving the Bible its status of sui generis.
The concept of loving one's wife as Christ loved the church was totally foreign and countercultural in its day. Again, God's standard of behavior within the family unit consisted not so much of the nitty gritty and minutiae of justice writ small, as in the Code of Hammurabi (18th century BCE), but of justice and love writ large from the mind of a just and loving God who holds His people to a divine standard.
As Doster and White observed at DartmouthApologia.org:
"In the first century Greco-Roman world, women were considered naturally inferior to men. They were viewed as a commodity exchanged by marriage and held to a strict moral standard from which their husbands were excused. They were deprived of any form of independence and forbidden to exercise authority or influence of any kind. As the great Roman orator Cicero wrote, 'Our ancestors, in their wisdom, considered that all women, because of their innate weakness, should be under the control of guardians.' Today, in a progressive society that values the rights and equality of women, Christianity is often characterized as the extension of this misogynistic worldview. Yet the history of the early Church tells a dramatically different story. The Christian teaching that in Christ 'there is neither Greek nor Jew, there is neither slave nor free, there is neither male nor female' (Ga 3:28), shocked and offended the ancient world. [Within Christian circles] women were valued equally with men. In marriage they were partners, not property, and both husband and wife were expected to adhere to the same set of moral standards. They were allowed to participate in the Church as individuals, and to hold positions of authority and influence in accordance with their spiritual gifting. Contrary to modern day perception, it was the Christian teaching embodied in the early church community that provided the catalyst and foundation for a revolution in the rights and dignity of women."
In conclusion, "Christian teaching" as cited by Doster and White requires that Christians worldwide "live out their faith" within a culture whose values are often diametrically opposed and even hostile to biblical values.