(Not that anyone cares about my two cents... but I'll toss 'em in here anyhow...)
I do because you're open-minded and usually don't cling on conjectural assumptions that turned into dogma, so thanks for your feedback.
It seems to me that this thread is mainly a few guys passionately arguing their opinions (dare I say evangelizing!). Depending on your assumptions, either position could be valid.
Yes, because of different interpretations of "canon". I'm not aware that Gene Roddenberry left us with a Rosetta Stone how to interpret canon one way or the other.
I enjoy following Robert Comsol's mental gymnastics, but, if I have one criticism, it's that one need not be so violent about where one draws the G.U.T. line. You, sir, rail against Unified Theory attempting to tie together the entire franchise, yet embrace a Unified Theory tying together the original 80 hours, even though the evidence for an evolving backstage concept is readily demonstrable no matter where one draws the G.U.T. line.
This must be a misunderstanding. I do not rail against G.U.T. in general. On the contrary I love to see gaps filled and back stories provided which constitute threads to weave a larger tapestry of the vision that is Star Trek.
I only rebel when I see threads introduced which deliberately or accidentally remove already existing "threads". Usually the result of inadequate research and/or lack of interest ("It's just a Show") and/or personal bias (e.g. Romulan Star Empire crest featured in "The Enterprise Incident") or a combination of either three.
To me that is essentially bad and/or unethical behavior and I for one can't possibly accept this as a "truth". I do not try to find fault. On the contrary I look for solutions how to rationalize such latest revisions and alterations but, and again, it's these revisions and alterations that require a rationalization, then, but
not the source material.
I think it's fair to say that Gene Roddenberry and co. were probably on-board with the Constitution-class nomenclature from early on and that Kahn's viewer graphic, later recycled as Scotty's Tech Journal were intended to indicate a class for our intrepid hero's starship.
Sorry, but I think the exact contrary is the case here. D.C. Fontana said they should establish the names of the "Starship Class" sister ships of
Enterprise. Bob Justman wrote back "Enterprise Starship Class". In the other threads it was suggested he didn't mean it (how can we be sure?), but then he could simply spared himself the letters and just say "Enterprise starships" (just as many here spare themselves the typing when they use "Connie").
And the description of the mission and men clearly reads "
Enterprise-class starships".
Had the Producers seriously accepted Constitution Class they would have never made any statements such as this because these definitely suggest otherwise!
And, again, the schematic of "Constitution Class" just popped up in the context of one of several "starship manuals" in "Space Seed".
My reason for thinking such is that the original Star Trek Concordance which was made while the show was still on air states as much, and it was written my Bjo Trimple, who seems to have had extraordinary access to cast and crew while assembling her references.
In the other threads the possibility was suggested that Bjo was deliberately replacing "Starship Class" references with "Constitution Class" and that she simply adopted Greg Jein's NCC registries (I had always wondered where these had come from until I finally read Greg Jein's treatise. It is a must-read to understand where "Constitution Class" came from and especially
how!

).
Also, GR's use of the term in his TMP novelization and in ""The Naked Now" (the first production episode of TNG, when GR was still very much involved with the show) suggest to me that he was perfectly fine the Enterprise being a Constitution-class starship.
Valid Points. Of course we need to consider that Gene Roddenberry personally and with his signature authenticated the official TMP blueprints which said "new Enterprise Class" which is also the designation that ended up on the bridge simulator door sign.
It's possible that Constitution Class starships (16th design) are stronger than Enterprise Class starships, so in the context of the TMP novelization you'd wonder how your strongest starships would cope with the latest Klingon Battlecruisers.
Maybe I'm the only one to see a pattern in the M-5 attack on the other starships in "The Ultimate Computer". The M-5 didn't take out the lead ship but first and foremost a stronger one of the Constitution Class (
USS Excalibur, NCC-1664).
As for the original scene in "The Naked Now", as
blssdwlf has repeatedly noted, we do only see an
Enterprise refit shape which Picard comments with "Constitution Class" (which NCC-1701-A obviously is). Here they could have used the erroneous screen graphic from ST III but still they didn't.
If the Constitution Class had been the first design series resembling the later NCC-1701 and the last to undergo a refit (NCC-1701-A) it stands to reason, IMHO, that 80 years later people in the 24th Century no longer make a Vulcan-style differentiation but refer to a particular line that's remembered best, i.e. the Constitution Class (which is my personal rationalization for "Relics" and the subsequent DS9 Episode with the erroneous deck numbering).
And I've presented a simple G.U.T. rationalization without convolution (and which has the advantage that it doesn't work at the expense of the original creators).
Bob