Narkissos,
Cursory reading has lead many unbelievers to come to conclusions such as God's complete soverienty, the deity of Christ (being God), and the Trinity. So I can just as easily use your same arguemnt for why we shouldn't just follow Greek grammar rules about why we shouldn't just use "cursory reading". And of course you agree with me when you say "You may also come to different conclusions just reading it (in context, in a cursory way), but I would submit it restricts the gamut of possibilities." Fruther, it's important to look at Greek grammar rules because koine Greek, as you probably know, is one of the most objective and straight forward languages, and especially way more then English.
If the definite article applies to everything listed after in verse 17, then fine. To me it was confusing why verse 28 has two articles and verse 17 only has one, which isn't placed in front of God. On top of this being good to know, the entire passage still perfectly coincides with Trinitarian theology.
And you seem to be emphasizing chapter 17 as the crux of John's gospel. There is a lot more to it then saying that the saints will be one with God as God is one with God. Once we consider the whole of John, and the whole of Scripture, we see that being one with God for a saint can be in some way identical to how Christ and the Father are one, and in some ways impossible. For example, the saints will be glorified and forever made unable to sin like Christ and forever get to increasingly know Christ, but do not become omniscient or eternal like Christ. All this has to be considered when coming to conclusions from John 17, or 10.
Therefore, it's not nessecarily a weak or strong emphasis of the first half (or second), but both/and. It's a matter of looking what sense it's both weak and strong in both halves by looking at the whole of John and Scripture.
Going back to your statement "You may also come to different conclusions just reading it (in context, in a cursory way), but I would submit it restricts the gamut of possibilities", this is something I agree with you on. However I would add that one needs to understand Greek grammar rules and have also learn a richer understanding of Greek words to limite possibilities even more! And like I've stated, many, after doing all this have come to the conclusions of the Trinity, the Deity of Christ (as God), and the complete soverignty of God (even by non-Christians at times), so you're only begging the question when I ask you "did John call you", because many would do all this and still disagree with YOU. For example you are only left to say "That's definitely not the picture I get from the Fourth Gospel."
I don't limit my conclusions to "the Fourth Gospel", but to the whole of Scripture since it is all God's special revelation to us. And how do you not come to the conclusion that God is eternal and that we are not in John, when it begins with "en arche"?! "En" is imperfect and without derivation of a beginning, and "arche" has a beginning at a point in time, hence the world in which finite believers are created in.
How are you using the word "anachronistic"? That it came about through a traditional or historical belief? If this is so, then I'm going to have a hard time believing you because Tertullian first cointed the term "Trinity" hundereds of years before the Council of Nicea.
And the doctrine of the Trinity is "a later dogmatic synthesis made up of a patchwork of unrelated texts and a lot of "unscriptural" reasoning in between."? One could have that opinion about any doctrine!!! That's actually fundamentally how we get doctrine, namely, "patching" verses and contexts together! Wow. And it's your assertion that these are "unscriptural" with regards to the Trinity. I'm affraid you'll have to start with a Biblical example to convince a Bible student of this, not just offer your blank assertion.
"agree on the principle of "using" the text rather than reading it." Again, like I've pointed out, both are needed, and for reasons according to your own logic. And I find that JW's are more prone to be "Bible readers" not Bible students, hence why Jesus doesn't get to be God in 1 Cor 11:3 when the Father is said to be greater then Christ, yet it's never considered that this can't be referring to an ontilogical sense since man isn't said to be ontologically superior to woman!!!