Looking forward to seeing if there is a script dependency too. If it is a script blunder it would be from not explaining why Deck 5 was restored since Scotty's line about stuff shutdown "all over the ship" covers potentially any and all decks. IMHO.
Yes, I agree that the "all over the ship" line was included to cover a lot of random territory, however, my thinking is that if deck 5 was not intended to be mentioned at all,
and since we did see Kirk using his quarters later in the episode, then there would be no reason to assume that deck 5 was originally intended to be one of the decks/systems shut down in the first place, and therefore no reason to speculate on whether the power was subsequently restored for that deck. in other words, as I said above, it would then make sense -story wise- that
M5 never shut down power on deck 5 because, unlike decks 4 and 6 which are the other berth decks specifically called out, and for which there were no crew aboard to use, Kirk and his senior staff are aboard and probably would want to use their quarters -which in other episodes are established as deck 5- from time time during the mission.
Not sure. It is possible Sickbay was on Deck 7 in "The Ultimate Computer"?
But in "Elaan of Troyius" when Kirk takes Elaan to Sickbay he drops her off at Deck 5 which is how I remember it.
As far as Sickbay goes, "EOT" isn't very specific, because Kirk first tells Elaan to "go to sickbay" because "its the best protected part of the ship" but she doesn't comply, and then several minutes later -when the immediate threat seems to have abated a little -and Kirk feels he can leave the bridge- he then escorts Elaan into the turbolift and orders "deck 5" to the computer, but note he doesn't say "Sickbay -deck 5" so it's possible to surmise that due to the reduction in tension, that Kirk has changed his mind, and now feels that she will be safe enough in her (Uhura's) quarters, and his intent is to go there? However when Spock reports that the situation is heating up again, Kirk just drops Elaan off on deck 5 telling her to go to Sickbay on her own (by catching the next turbolift?), while he hurries back to the Bridge. Interpreted this way, the deck location is left ambiguous as to whether sickbay is on deck 5, or some other deck, such as deck 7.
Argh. I thought "Day of the Dove" established Sickbay on Deck 7. But now that I think about it, I believe "Mirror, Mirror" has a Deck 5 reference as well, so you're right. I wonder why the blueprints (as far as I know) put it on Deck 7.
The original source of the "Sickbay = the center of deck deck 7" association comes from "The Making of Star trek" which also posits an 11 deck saucer (for which there is plenty of corroboration from the episodes themselves) and as such, it would definitely qualify as "the best protected part of the ship", whereas a deck 5 location -in an 11 deck saucer- would not.
More likely the writers just counted the levels down from the Bridge to determine what was the largest (and therefore "main") deck...which was Deck 5.
Yes, I agree completely, it seems that throughout most of the series "deck 5" was thought of as the "main deck" on which was found Senior Officers Quarters, Sickbay, Botany Lab (?) Transporter, etc. In fact, deck 5 is mentioned more often than any other deck!
When was that graphic made, though? There's definitely at least one cutaway preceding it, the one on the bridge set engineering console and next to the turbolift.
Yes, that's part of the problem with interpreting this stuff. In both graphics and clues from dialog the ship went from ~540 ft long to ~947 ft long and possibly back again, before being reestablished at 947 ft again. And there were a succession of three story editors during the 1st season, each with their own ideas of how many decks were in the saucer, either 8 or 11, and at one point the writers guide even said there were 20 decks in the saucer. Because of this and other reasons, I tend to not put too much emphasis on the plethora of contradictory graphics, and stick with the onscreen dialog cross referenced with scripts whenever possible.
Deck 7 wouldn't be the most protected area on the ship, especially since all torpedo blasts occur in the lower saucer hull.

I put Sickbay on Deck 5, port side. Of course, there are several medical facilities on the ship.
That would work great for Jefferies cutaway graphic we've been using above, and an 8 deck saucer, but this graphic was never seen onscreen. But there's lots of dialogue favoring an 11 deck saucer, which would make the center of deck 7 "the best protected part of the ship".