One thing struck me about the Saladin/Hermes plans: the plans show an ENT-style pair of shuttlecraft launch bays on the underside of the saucer.
Not "ENT-Style" but rather "original Matt Jefferies concept style."
The shuttlebay is supposedly located on Deck 8. (I thought that the saucer only had 8 or 9 decks, but not according to these plans.)
Nope, it's been uniformly accepted that the TOS 1701 had 11 decks in the primary hull ever since the early 1970s and the Franz Joseph blueprints. I have NO IDEA where you'd have gotten the idea of "only 8 or 9 decks." As far as I know, no published reference has ever so much as hinted at that.
This hangar is only on one deck; there is not "high bay" spilling over onto Deck 7.
Which means that the shuttlecraft carried by this ship need to fit into a single deck height. Not impossible... but probably, therefore, not being the TOS shuttle design as we know it, huh?
I also noticed a full-size Engine Room located at the rear of the saucer just ahead of the impulse engines. I would expect that the saucer's underside undercut ring to cut into the floor space of that room.
That's how the FJ design had it... and that, ultimately, came from Gene Roddenberry's tendency to claim credit for work which wasn't his own. At some point someone asked where the Enterprise's engine room was, and his response was to put it there. However, Matt Jefferies always intended for it to be in the secondary hull, and virtually everyone in the original series production staff (except, apparently, Roddenberry) knew that.
However, when Roddenberry said that's where it was, people went along with it. I always HATED that... in part, because of the exact reason you gave. And when the first cut-away painting came out that Paramount had approved with it being in the secondary hull... that little bit of Roddenberry-ism finally went away, never to be seen again.
Another thing I've noticed about all of these plans is that there is no space for matter/antimatter fuel storage. None whatsoever.
Of course not. This was before the TMP redesign, before TNG... back when the original intention was still in place.
The antimatter and matter used in the M/AM reaction was stored in the nacelles. The main reactors (NOT "WARP CORES") were in the nacelles. And the warp field generators were in the nacelles.
I really didn't like it when they put the M/AM reactor in the secondary hull in TMP, but could accept it (since it was a dramatically revised design). But I really hated it when everyone started asking dumb questions like "where is the dilithium articulation frame... the warp core... the plasma conduits... in the TOS ship. Those are TNG-era terms, not "Star Trek" terms.
So... the matter collection... the antimatter generation... the matter storage... the antimatter storage... the matter/antimatter reactors (plural)... and the warp propulsion system... are ALL inside of the nacelles.
Does anyone else want to chime in on these plans and whether or not everything "fits"?
It fits just fine. The problem is that stuff that came later DOESN'T "fit" with the original idea from "Star Trek."