The years of research and development were spent making sure it didn't end up in self-aware megalomaniacal computer storage

The computer was tasked with creating an opponent that could defeat Data. Doing so required analyzing Data to assess what would be needed to fulfill that request. And the most complete source for that info would be the transporter, which has broken Data down at a molecular level and rebuilt him numerous times. And using that info, the computer imitates Data's own neural net as a baseline, then grafts a holo character on top of it. That these the things are compatible and can be so easily integrated is also demonstrated in A Fistful of Datas.

The EMH had to be built from scratch, as there wasn't a way to essentially steal Soong's life's work as a shortcut.

The Enterprise-D, being a giant showpiece ship had the most bleeding edge holodeck of the era. The holodeck uniquely incorporated a lot of TOS advanced alien technology, which Starfleet engineers mostly understood. Mostly. There were some hiccups.

The tech was refined and only in-house developed and vetted holotech was issued out following incidents such as Moriarty. It takes a lot longer to research and create from scratch than it does to plug in some alien tech or coding that you think you understand.

The EMH was not a janitor or menial laborer. It was a highly skilled holographic entity that was repurposed below its abilities. The repurposing was not a decision made to make use of the EMH’s abilities but out of spite by a jaded creator.

Also, whenever you notice something like that, a Q did it.

Moriarty was draining enough of the Enterprise's power to cause brown outs and was using a huge chunk of the main computer's processing power. The EMH is much more efficient. He's also probably more sophisticated in other areas, like precision movement or being able to function in arbitrary non-holographic environments.

"Make a hologram of the fictional character Moriarty but make him aware that he's a hologram" is fairly simple compared to making a hologram who can act as a ship's emergency doctor.

Something to do with the Holodeck being able to stabalize holomatricies better than... Whatever the janitor programs were using.

But also, I'm not sure any of the enterprise crew were able to reproduce a Moriarty quality of intelligent from the Holodeck again. He was, a fluke of luck, a glitch, where as the janitors were intentionally designed, and coded, and were thus reproducible on demand.

https://xkcd.com/1425/

The downfall of Zimmerman wasn't the technical stuff; it was him injecting his own, abrasive, personality into all of them. And then also using Andy Dick and calling him an "upgrade." 🤮

On a more serious note: They heavily imply all those janitors are just as capable as Voyager's EMH. Which makes their situation way shittier because they know they are more than just tools.

The holodeck on the enterprize has been insane ever since the Binars messed with it. Theres never any telling when a seemingly random "incident" will occur there and their hack was so sophisricated nothing ever comes up in diagnostics.

To bad the Binars aren't interested in doing this type of things for reasons other than distracting Riker.

What I still don't get is how Vic Fontaine is as self-aware as Moriarty and nobody questions it or even gives a shit.

EMH was designed to be a doctor, not a janitor. I bet a lot of the work behind EMH was in proving mathematically that it would not harm patients (while at the same time, understanding that some temporary harm might be needed to save a patient's life). We see how core this is to an EMH's identity when in Voyager, the doctor goes crazy after not being able to save a crew member.

Meanwhile, Moriarty had no safeguards. That's part of why he was so dangerous to the crew of the Enterprise.

The enterprise is a larger ship, it has 10x the crew as Voyager. 10x the size of a ship would be needed to house 10x the crew, which means 10x the computing space

presumably zimmerman better understood the dangers implied in flippant worded commands. kindred spirit, living by "if ignorance is bliss, give me agony."
contrast to geordie whose chipper demeanour carries him further without learning such lessons, less e.g. bitterness reflected back to teach him he needs be careful, or his creations could cost many lives. and besides, the rest of the crew and all the safety's are around and ready to pick up the slack. zimmerman, no such supports. he programs with holyC.

The Ent-D computer is at least limitedly sentient. Moriarty and especially S7E23 Emergence confirm this.