Don't get me wrong; I (still) love Star Trek! It occupies a big space in my heart and on my shelf. My contention is that the holodeck was a mistake. It's a fly in the ointment that made me say "blurg" instead of "wow". Here's the deal.
I lean towards benefit of the doubt when it comes to books and videos for entertainment. All I ask is that a story not make me mad. The problem with the holodeck was that it made me mad. It disrespected two of the few rules I have.
When it came to the holodeck, the science seemed silly, and it was logically loopy.1
The holodeck usually gave me a bad case of the "Yeah, buts!"
◈ The holodeck is said to use replicator and transporter technology. Yeah, but what about the sparkle effect? Transporters and Replicators sparkle and make noise when you use them. Holodeck: no noise, no sparkle. Also, Transporters and Replicators take a few seconds; they are not instantaneous.
◈ The holodeck can apparently simulate large virtual spaces, including the outdoors. Yeah, but what happens when people can see each other from a distance? If you can see each other, but you're pretty far apart, the other person should look small. What if someone is yelling at you from a four-story window or across a field?
◈ The holodeck can apparently simulate motion over a large virtual distance. Yeah, but what about inertia? If magic transporter effects move the scenery around you, your body has no velocity and no momentum. You can tell when you're moving if you speed up, slow down or change direction!
◈ Yeah, but how did it make Moriarty? Data is considered unique in the Trek Universe, in part because he is a machine intelligence. But apparently the holodeck's computer can make a pretty good one based on very simple specs.
The holodeck has a safety mechanism that prevents it from harming humans. Yeah, but it seems to break frequently, and it can be disengaged. There's very clever children on the Enterprise. You'd think the "holodeck safeties" would be at least as hard to disengage as, say, your cable box parental controls.
How can you build something that dangerous and not have a big, honking OFF switch?2
Why isn't there an OFF switch? Why is it so hard to shut down? It has to be getting power from somewhere; there must be circuit breakers somewhere. Otherwise, get a phaser; cut some power conduits!
This episode relies heavily on the holodeck and its magic powers. Commander Riker is accused of killing a scientist. Picard and company hold an investigation in a holodeck version of the scientist's lab.
It turns out that the holodeck representation of the scientist's machine is so accurate, it actually works! You have to wonder why anyone would bother to actually make anything if holo-technology works that well.
The story is hoist by its... well you know. Geordi tells us the machine needs coils made of a special material, which the scientist had ordered large quantities. (Seems like he would have been smarter to just use a holodeck–no backordering.) In the end, the holodeck version works so well it explodes–just as the real one did at the start of the episode.
The first explosion destroyed a space station and killed the scientist. The holo-explosion of the machine in the holodeck.....does nothing. Only Picard and company remain, sitting in their chairs in the familiar yellow-grid of the idle holodeck. (Presumably they were holo-chairs and a holo-desk; why bring in real furniture!)
On the one hand, things in the holodeck are as solid and lifelike as the items on the bridge. You can sit on the chairs and climb the trees. But on the other hand, they can vanish harmlessly in a nano-jiffy. Transporter/Replicator technology sparkles, makes noise and isn't instantaneous. It can't be both ways.
In the season two episode, Geordi tells the holodeck to create an "adversary capable of defeating Data." The computer creates Sherlock Holms' nemesis, Moriarty. Pretty amazing trick for the computer; all it took was a single command from Geordi.
I guess you had to get the wording just exactly right.
In the much later one, Moriarty returns to plague the Enterprise. Lesson to be learned: be really, really careful what you ask the computer to do. It might create a virtual enemy that can beat you!
If Moriarty is considered an intelligent life form with whom Picard negotiates, what does that suggest about his giving orders to the Enterprise computer? After all, the computer created Moriarty; what does that make the computer?
Picard and Riker and Minuet. Another amazingly lifelike simulation.
A one-in-a-million freak event causes the holodeck safeties fail and endanger Picard, et alii.
A Dixon Hill story. My question about bullets is: does the holodeck simulate the gunpowder exploding? Holo-chairs are real, you can sit on them; what about a holo-gun, how real is it?
A one-in-a-million freak event causes the holodeck safeties fail and endanger Worf, et alii.
Some think a Western episode indicates the death knell of a show with spaceships. ((Firefly was a Western with spaceships—totally different concept.)) How about a Western in the holodeck? Combine that with a holodeck malfunction, and you gots yer se'f a rip-rootin' ol' time!
I can think of many good stories that could take place on a "real" holodeck. By "real" I mean a holodeck that doesn't rely on magic transporter-replicator technology. All we need to assume is advanced 3D photo and display capabilities. Would you trade any of the episodes above for:
◈ Suppose they displayed an image of every solar system they visited (as they entered the system), and a view of any planet they orbited. This could have been a semi-regular feature, like 10-Forward; a background for scenes. Imagine Bev and Troi apparently walking around, in space, in orbit, around this week's planet!
◈ Mount a holo-camera on a probe, and fire it off into something interesting. The visuals could be very creative. The holodeck is an "effect" in real life, so it can look like an effect.
◈ There was an episode where Geordi used the holodeck to save the Enterprise and fell in love with the holo-image of a scientist. I would have liked to see Geordi walking around inside the engines! Wouldn't you have liked to see that?
◈ We have CAT-scan machines now that generate 3D images of the inside of your body. Imagine if Doctor Crusher walking around inside a patient's body before surgery! What if it had been a really weird alien!
◈ In one episode, a hull-eating space virus infected the Enterprise? Imagine Picard and Geordi taking a walk around the Enterprise. Imagine the two of them standing on nothing beneath the gentle curve of the saucer!
I can see so many ways to add fiction to the science without completely compromising the science. I've always believed Science Fiction can be both popular and critically robust. I believe that Science Fiction, in particular, can sometimes even be educational!
 It's going to be difficult to avoid using the obvious pun, "Hoist by their own Picard."
 Sometimes I wonder why Picard didn't just weld shut the doors.
 Season 3. A Matter Of Perspective
 Season 2. Elementary, Dear Data
 Season 6. Ship In A Bottle
 Season 1. 11001001
 Season 1. The Big Goodbye
 Season 6. Fistful Of Datas