Temple of Ranma's Sailor Senshi Seifuku

Why didn't the mercury computer tell the inners what happened to the Moon kingdom? It should have been scanning even after Mercury's death.

Why didn't the M.computer have any data on the Uranus, Neptune, Saturn, and Pluto? At worst they would be like a kingdom next door, or legendary people.

Why didn't the M.computer have data on the talismans and grail? They are clearly Moon kingdom weapons.

Why didn't the M.computer have data on pure Heart crystals, dream mirrors, and star seeds? They are clearly things that senshi should know about.

Why didn't the M.computer have data on the big bads? It seems like a few of them at least had some run ins with the Moon kingdom.

It seems like there is a lot of important data is missing from the Mercury computer that at least would have been helpful. It seems like there should at least be general information about the big bads, all the sailor senshi of the Moon kingdom/Sol system, the talismans, the grail, pure Heart crystals, dream mirrors, and star seeds on the Mercury computer.

Why would this information not be in the M.computer?

My theories about those things is something like this. (Mostly Anime-verse)

(1)The Mercury Comp didn't have any 'sensitive' data at all to begin with, because it was a training tool for a Senshi trainee, with only the most basic data stored inside. And Ami-chan got a brand new version when she went Senshi for the first time.

(2)As for the Outers - well, anything to do with Sailor Pluto and Saturn were probably 'classified infomation', and it's possible that things were similar with Uranus and Neptune, too.
My guess is that the existence of the 'Outposts' or 'Kingdoms' or whatever they were actually called was common knowlege, but the details about the Outer Senshi were not.

(3)Whatever that passed for a Main Data Bank for the Moon Kingdom was long gone, so there was no way to update things from there, either.

(4)The Mooncats don't really know much more then the girls either, since they were Advisor Trainees of a sort to begin with, and they didn't have much of an access to much of a databank to begin with. (In the manga, we see the 'cats hanging out with the Moon Princess and her friends - the impression I got was 'glorified babysitter' 'governess/tutor' 'chaperon', etc. In the anime, Artemis didn't know about Pluto at all till Queen Serenity just happened to tell him about her)

(5)The Talismans, Grail, etc are not 'Moon Kingdom Weapons' - they are probably naturally created things that 'just pop up' when the conditions are right in the Sailor Moon Universe.
The Deathbusters wouldn't have known to go looking for them if they were things that didn't exist outside the Moon Kingdom, after all.

It's probably because the mercury computer's function does not serve as a general data compiler or database. Whenever in use, it's always applied for general analysis and calculation, usually in conjunction with her visor. If it stores anything, it'd probably be information related to the use of strategies.

In the manga, they have access to a computer under the arcade, but it doesn't seem to serve a purpose too far beyond the Mercury computer, except its performance is much more exceptional; and it likely has a connection to the computer(s) on the moon, too. In the manga, the moon's sub-computer was still online by the time the senshi went to the moon. After the defeat of Metallia, the moon palace was restored and (I'm assuming) both the main computer and sub-computer were back in operation, as well. If there's any data about the things listed above, that's where you're likely to find it.

But Queen Serenity was rather secretive, causing a distinct disconnect in which senshi knew what. That alone probably suggests that some information was considered too sensitive and thus unsuited to be left for just anyone else to find. And, despite Usagi being the princess, which, assumedly, places her in a higher station, she's probably more in the dark about things in general than the senshi that personally protect her.

It could be just a specialized tactical processor designed to work in tandem with the Silver Millennium network, with the database residing on the mainframe while the M. Computer had only a limited cache or none at all. With the cache reset, Mercury got a set of analytical software working in the emergency autonomous mode, an array of scanners to gather data on her own -- but no any previously stored data, as the network is now defunct.