I appreciate the insights Dane. As I reflect on the issue of 'certainty' (and critical text advocates use this against the TR position), to my mind there are three issues:
1. The KJV itself questioning some readings by putting them in italics. Eg, John 8:6 (last part of verse) and 1 John 2:23. The NKJV has these in normal text.
2. The KJV questioning some verses re their authenticity Eg Luke 10:22, Luke 17:36 and Acts 25:6. It was the KJV footnote questioning Luke 17:36 that took me to the critical text for some time. I reasoned if the KJV 'questions' some texts, I cannot blame the CT Bible for doing so.
3 Textual emendations such as Rev 16:5 and other 'difficult' passages such as Eph 3:9. When James White and Geoff Riddle debated Eph 3:9 I was not convinced by Geoff Riddles defense although I agreed with him that the text should not be determined 'naturalistically'. When James White made comments on Eph 3:9 he argued that God works in history and thus he could not accept a reading with extremely little mss support.
Now getting to my point, the reason why I argued for a 'light' revision of the TR, is that WCF 1:8 "kept pure in all ages" is an important standard. Therefore we need to determine a reading that has been in clear use by the church in all ages. I think there may be a case to determine the best TR reading in light of this, even if it means occasionally using the Byzantine Priority reading when it is clear the reading has been in use in all ages. Is it better to use the Byzantine Priority reading for Eph 3:9 for example?
Here you illustrate the point I have been making. The editions of the TR before Beza's 1598 edition seem to me to adhere to the standard 'kept pure in all ages'. The KJV rendering does not. Can one not argue that the Geneva Bible is correct here?
Here on the Puritanboard you have esteemed members arguing for a Sturzian approach to providential preservation. Others ask why tie providential preservation to a specific era in church history. It seems to me a consistent TR revision would help answer some of this.
Here is my promised response to your other points.
1. I would again stress the need not to read too much into the italicization. Especially in 1John 2:23, the last clause in question being found in some of the texts the KJV translators were working from. It is absent from the Complutensia, all of Erasmus' editions, Aldus' (1518), all of Stephanus' editions (though it is present in the margin of the 1550 and 1551), Beza's first two editions, and Tyndale's NT. It is present in the editions of Colinaeus (1534) and the last two editions of Beza (the 5th [1598] being the main text of the KJV translators).
2. I have no problem personally when the KJV, NKJV, or any other translation adds footnotes giving background information on a reading. Many KJVO's and brethren in the TR camp think this means the translators are "questioning" or "casting doubt" on the text, but I think that is a stretch. If they were truly questioning it, they would put brackets around it, as is done in the modern versions, and even then, the fact that a translation places a reading in their main text shows that it is of considerable authority. So, to agree with you, I dont have a problem with any translation giving background information on a reading to inform the reader.
3. A conjectural emendation is when someone emends the text based on nothing but conjecture, (like the NA28 critical text does in 2Pet. 3:9, adding in the negative particle, οὐκ "not", based on absolutely no Greek manuscript support). This is not what Beza did in his 1598 edition. In the footnote he claims to have "restored the reading 'and shalt be' from an old manuscript of good report". Whether he was right to do this or not, this is not the same as conjectural emendation. Dr. Riddle has an entire Word Magazine diving into this footnote, where he translates the Latin note. Regarding Eph. 3:9 κοινονία "fellowship", I would not classify this as a textual emendation, since many of the TR editions have it. True, there is no extant manuscript evidence for it, but that does not equal it not being an original reading, since the editors of those TR editions had to have gotten it from somewhere, and what manuscripts are extant today (at least the ones we know about) do not necessarily represent every manuscript that has ever existed. Personally, I have no issue with either reading, but I err on "receiving" the reading as it has come to us in our vulgar translations (KJV/NKJV). The point to take away from the debate, as you point out, is that regardless of which reading we take, "fellowship" or "economy", we should not approach this naturalistically. Both readings are found in the TR tradition.
In response to your point on a new edition of the TR, I dont think it would harm anything to have a "critical" edition of the TR, that shows all the readings of the various TR's (possibly from the Complutensian to Scrivener), but I also don't think it would solve anything. Interestingly enough, we already have something similar to this in Scrivener's 1881 annotated TR (which is sadly out of print). The appendix in the back is where I have gathered much of the information I have shared with you, regarding different editions of the TR etc.
I hope that helps. It seems to be that the rhetoric on both sides (of which I have played a role in the past) has really hampered this discussion and only caused both "sides" to entrench themselves in sometimes untenable positions, or back themselves into corners of circular reasoning.