The type font on the hull of a starship being vaguely reminiscent of the type font used in TOS before being replaced by something more complex in the final shot... if the rest of your evidence is of a similar nature, I'd say this conclusion is probably wishful thinking on your part.
It's just a font, neither is particularly more technically advanced than the other. If anything, the TOS-ified version is "more complex" because of the added outline, while the final version uses an off-the-shelf font, rather than the bespoke Trek version with pinstripes and the "1" that doesn't look like a "7," which was made for TMP and used through Nemesis (with occasional lapses). Even the JJ movies, using off-the-shelf Eurostile/Microgramma, fixed the "1."
Even then, I'd be happy to concede that I'm probably deluded, if it'd been a one-off thing. The comic-con teaser used Microgramma. So did the leaked test footage from the first VFX team. Concept art used both the TOS-style and Microgramma, ping-ponging back-and-forth or, perhaps, being revised for consistency after the fact. For instance, the
black-and-white drawings of the random starships all use MG, but most of
the colored drawings use TOS-style.
Discovery and
Shenzhou are notable exceptions, except there's
production and
promotional art of them using the old-style markings, too.
So that means they switched back and forth, possibly more than once. And look closer at that shot. The lines of the ship are the same. The little nurnies. Even the pattern of the hull plating texture and some of the tears in the hull. The shot was the next thing to finaled. This was a change of mind, late enough in production that VFX shots were already being locked for the pilot.
As for the rest, the short version is that vintage Trek design keeps sneaking in at the margins. The Starfleet props are incredibly derivative of what's gone before (the communicator uses the TWOK grill. The rifle has the cowl from the Phase Pistol. Who'd even
want that to be referenced visually?), but the Klingon... everything... is totally different (excepting the language, logo, one weapon, one and a half ships, and one guy's outfit). The computer screens are all modern post-Iron Man glowy lines on black... except for the movie-era alert indicators. The nacelle caps were going to be red... until they were blue (except on non-hero ships). The soundscapes are a random hodge-podge of TOS, TNG-era, and new sound effects, thrown together so haphazardly that it was genuinely surprising that when Burnham hacked the communications in "Prologue" there was both a TOS-ish computer screen along with exclusively TOS sound effects. The ships, as aired, tended to draw on the TMP-era design language, but when we saw the
Enterprise, it had TOS versions of detailing DSC had already established a TMP-preference for (pennants and such).
There's no unity to Discovery's design philosophy. It doesn't know what it wants to be, so it's trying to be everything. Is it a reboot or is it a prequel? Where on the spectrum does established production design fit between "vague inspiration" and "gospel truth"? The final episodes of the season, and especially the final minutes of the finale, showed that this isn't just a visual problem. They have no theme, no guiding light. Things are just happening, with no thought to what they mean, or what they commit the series to. DSC uses a generic, modern style for its computer screens, and then has a TOS-throwback display. Lorca is a manipulative spy whose a master at getting what he wants from people, until he's unmasked and suddenly just acts like an asshole rather than continuing to try and win people over to get what he wants. They go to painstaking extremes to cut off every possibility for peace with, or even victory over, the Klingons to build tension past the breaking point, so when it inevitably happens, it takes the form of a wildly convenient ass-pull rather than something that develops naturally from the characters and situation. They close the season with the less-than-mindblowing revelation that they're a Star Trek show, and give no indication of what they intend to do beyond cashing in on the fact that they have access to a pop-culture legend.
The logical reason for all of that is that people behind the scenes disagree on what the show should be, dramatically and visually, possibly on a subtle-enough level they don't even realize the dispute themselves. The biggest, albeit petty, public evidence of conflicting creative visions is the vacillating on how TOS-y the ships look.
I did take a second look at that trailer, and I did find a couple of other interesting things, ship-marking-wise. First, another angle on the
Europa, again showing the switch from TOS to TMP-ish markings (the red circle around the arrowhead seems to be being eaten by the specularity of the hull, but I'm pretty sure it's there based on other shots). The
Europa in the trailer also looks noticeably rougher than it is in the other shots, but I'm not sure if that's the texturing and modeling or the rendering quality being set to a "preview" level.
Way more interesting, though, is this image, from the aired version of the pilot, where some TOS-fonted markings on the bottom of the saucer slipped through in a shot of the
Shenzhou. It was tricky to find a shot where you could see what was supposed to replace it, so I added an insert showing the same marking on the Eaglemoss model for clarity.
