Not really exaggerating the engineering concerns, I'm an engineer. And specifically deal with designing submarines, which is somewhat related. What you're handwaving past, though, is the upside to your very complicated plan (and it is)...
Your argument from authority would hold more water if we weren't talking about starships in the distant future.
If you want the bridge in a safer location, just put it in a safer location.
I've already admitted as much. Logically, bridges should be deep inside the hull, which is terrible from a dramatic standpoint. Keep in mind that I'm balancing realism with dramatic concerns.
More moving parts = more chances to fail. One size fits all is often one size fits NONE, so trying to make this bridge module something that moves in the ship, and also a kewl shuttle, and also one of a magazine of several of them.... It just isn't going to excel at anything.
Yeah, just having the entire bridge be its own turbolift makes more sense. After all, aside from the interlinks to the consoles and viewer, it's no more complicated than the large emergency turbolift to the battle bridge that you mentioned earlier.
One thing I could do is have the captain's yacht be a harness that accepts the bridge "capsule", thus no longer requiring that the weapons, reactor and propulsion be built into the bridge.
If you want a viewport, put one in the front and put some limited helm control station near there, not the entire (exposed) bridge.
Only the very front of the bridge would be a window. It would be roughly the size of the Enterprise-D viewscreen. The rest is all holographic projection.
In an ultimate backup, someone could go there and steer manually. Or if you insist on the bridge having that window, the dedicated turbolift would be fine. It has the benefit of taking seconds to get from A to B, and only takes up a 5 foot cylinder worth of space vs. the massive cylinder that an entire bridge module would take up.
I'm imagining a maximum bridge crew of probably 10 to 12, so a five-foot cylinder is inadequate. You'd need a dedicated emergency lift, and that would require a larger shaft anyways. It makes more sense to have a larger shaft where multiple turbolifts can pass each other or travel next to each other when the bridge is not in transit.
Spooling cable can break, fray, catch on something, etc.
I never meant to suggest that a spool would be the ideal solution, only that it's A solution, that solutions exist, and that much better solutions will exist in the future.
If the ship takes any damage, it's easy to envision that big hollow tube in the ship being impacted, as even the slightest misalignment is a huge issue, and now the bridge (and crew) is trapped between stops.
If the first volley of your enemy's attack penetrates your shields and armor and bends a shaft in the very center of your ship to the point that it's no longer usable, then you're already dead. Moving the ship into the interior should be something that happens when you go to either yellow or red alert, not when you're in the middle of combat. By the way, your argument also applies to emergency turbolifts, so this is an argument against all exposed bridges, not retractable bridges specifically.
Having an entire magazine of them is a colossal waste. What percentage of your ship's volume are you dedicating to backup bridges that you may never use? Half of your ship is going to be a stack of backup storage bridges.
Only if your ship is
Archer Class. You're talking about dedicated space for the equivalent of five modules that are about 5 meters wide on a ship that's 20 decks high, 280 meters wide and 340 meters long sans the nacelles.
Why is the bridge module more effective than just having a yacht or other shuttle for more specific use? Because it now has to be (roughly) aerodynamic too, which is limiting your layout choices. Plus it assumes you want the entire bridge crew to leave the ship, otherwise you have to move people around first, which saves no time over just going to the shuttle. And the ship has no bridge during that launch, or you need an entire second bridge crew brought online first.
First of all, shuttles and yachts require just as much space as a bridge module, so the space savings argument is a lot less convincing here. The bridge does need to be somewhat aerodynamic (thought not as much as our current spacecraft), but I don't see that as being a significant hurdle. (A wrap-around viewscreen is going to lend itself to a rounded shape anyways.) It's not like I was planning to have a bridge shaped like a brick, after all. As for saving time, using the bridge as a yacht would likely not be happening in the middle of combat, unless you're about to ram another ship and want to get away, in which case you wouldn't want everyone leaving the bridge.
And you can't use the big stem to stern transport corridor, because it needs to be kept clear for the bridge module to move. Plus the big stack of extras you loaded in, so you need TWO of these big corridors, and one is full of wasted bonus bridges.
Uh, no. First of all, the bridge would travel the corridor in only a few seconds, and only traffic going out to the front of the ship would be blocked, because the rest can simply follow behind the bridge. There would only be a maximum of three bridges in a magazine: One primary and two for backup and training. When the primary bridge module is retracted, it would enter the bridge magazine, which would consist of a three module carousel, where it can be rotated into place and lowered into a yacht expansion module. If a bridge needs maintenance, it can be brought back into the magazine and a new one loaded in its place.
None of this makes logical sense, and is a massive waste of resources while not being as efficient as designing things that are actually good at what you want them to be. Dedicated designs that excel at what you want them to do is almost always better than making one kewl thing with a million moving parts that is supposed to try and do everything. A swiss army knife is convenient, but not if it takes much more space than the equivalent parts. Plus, if you are trying to use a knife for anything serious, you'd rather have a bowie knife than a swiss army knife blade. Same thing with a screw driver, wine opener, etc. Sure, you could just take 10 massive swiss army knives with you, but the smaller collection of actual tools will serve you better.
I'm not saying there isn't some merit to your argument, but there are two things you're not considering. One is that I'm deliberately taking some dramatic license, so I'm merely concerned with the idea being just plausible enough for the audience to suspend disbelief. If we were realistic, most combat-capable vessels would look like tanks with no windows.
Secondly, none of your arguments really stretch that plausibility. My design is no less plausible from an engineering perspective than most bridges in Star Trek. You seem to be holding me to a standard most TV starships don't meet.