As I began to put more thought into the issue, it seems to me that the two competing interpretations of the RPW as to its application mark the difference between the traditionalist understanding, and my proposed understanding of the principle. The traditionalist understanding of the RPW deals with things (i.e. "instruments," "psalms," "timing," etc), and thus could be properly termed ontological. The focus of the traditionalist understanding of the RPW has the adherent looking for things. Is the thing "X" commanded in Scripture? If it is, then yes, we can use it in worship. If not, then it shouldn't be used in worship. This is how the traditionalist tries to justify archaic positions such as "no instruments" and exclusive psalmody. They argue that instruments are not mentioned in the New Testament (simplified argument here), and thus they shouldn't be used in the worship of the church. Inasmuch as the principle is applied to things, their arguments seem plausible.
However, if we look at Scripture, the focus seems to be on principles rather than on things. One would be hard pressed to prove that God is concerned with things in and of themselves as much as He is concerned with principles regarding the usage of things, even in the Old Testament. When God prohibited the strange fire in Leviticus 10:1-3, God wasn't saying there was something ontologically evil with the strange fire. The problem lay in a violation of the principle of coming before God in a way He has not authorized, not that there is anything ontologically evil in incense, fire, censors and anything else. In another example, even the holy bread that was "desecrated," as it were, in 1 Samuel: 21:6 proves that the bread in itself was not inherently holy. It was their proper usage that is necessitated, which in that particular exigency it became proper for David and his men to partake of it. Thus, we see that holiness is not ontological, and thus worships is not about ontology, but principles.
If principles are what Scripture is concerned about, then the RPW should be teleological and not ontological. The whole traditionalist application of the RPW is thus misguided at its very core. They are preoccupied with the wrong things (pun intended), and read things into Scripture that are not there. Take the issue of instruments and note how little the Scriptures actually speak about them in comparison. The absence of instruments in the NT is taken to be a sign that instruments are prohibited under the New Covenant, but that is an argument from silence. Perhaps the absence could be that instruments are seen as indifferent (i.e. adiaphora), as opposed to their role in theocratic Israel? Now, a mountain is made out of a molehill and so much ink is spilled on so little biblical data.
We note one major proof-text for the "no instruments" position in 2 Chron. 29:25-30, which I had refuted in the past. As I had said back then, to claim that there were no instruments in the second part is an argument from silence. Furthermore, the whole narrative is descriptive, so it's ludicrous to even think that this text has any implications at all on the issue at hand. The whole argument that instruments are linked with sacrifices only proves that instruments were used when sacrifices were offered. But since sacrifices are offered during the "worship services," why link instruments to the sacrifices instead of to the worship? In other words, are the instruments there because of worship, or there because of sacrifices? To link it necessarily with the ceremonial law is an exercise in spurious association (otherwise known as "Guilt by Association"). Worship in the Old Covenant is also correlated with sacrifices, yet no one has ever suggested that worship is linked to the ceremonial law and done away with, as they have done with instruments.
A natural way of reading the Bible therefore suggests that God is focused on principles rather than things. Therefore, the RPW must be applied teleologically not ontologically. That of course means that worship is not an eternalist activity, but it actually changes with the cultures and the times, an altogether present truth that traditionalist minimize by calling any changes they'll accept "accidents."