But I don't know, and surely you can understand how people would get confused mixing those up on a first playthrough.
I'm confused by what you mean with "I don't know". The game explains the terms to you. If you read the text (not the datalog, the dialogue by the characters), you will learn what they mean. And if you forget, you can then look them up in the datalog.
I get that the game has it's flaws, but this is something I will blame the player for. Everyone can learn three new words. And, again, you can always look up the datalog, if you forget what is what. Which is, imo, a very good combination.
There's also the fact that a lot of crucial information to understanding the context and lore of the game is not ever organically, diegetically explained through exploration or dialog, but trapped/hidden in game menus.
I honestly don't know what about the information that is only in the datalog would be crucial. I did read everything in the datalog, so maybe I overlook something, but I think what you need for the story, you will learn without ever touching the datalog. It only contains extra details, that might be interesting, but not necessary.
Personally, I also don't really understand what's so awful about that. Seems like a decent way to give the player information, that they don't need, but might be nice to have. Sure, could be better, but I don't understand why people think it's so awful. I guess that's a preference thing. I also don't get, why students need museums, for History to be interesting. I don't need to touch anything, or see it in front of me, text is enough for me. So that might be just me.
But that's the thing. We experience almost none of it. It's not like FF7 where several hours are dedicated to exploring this big city you start out in, getting to know its inhabitants and seeing all kinds of angles to things. Feeling alone is fine, but for it to have weight you need to contrast it with something. And that's why FF7 is brilliant by contrast. When you head out into the open world, the big empty spaces feel more impactful because you have that initial reference point of the claustrophobic city. 13 never really did that, because it never let you actually explore Coccon or meaningfully interact with its people. And it's a shame because clearly someone along the line created a whole bunch of lore that would have been interesting to experience and express first hand, the game just didn't do it.
I say this all btw, as someone who generally enjoyed my time with the game and have been an apologist for it over the years. But I'm very realistic about its failings, which are mostly on the narrative end.
I agree, that it would be good to have a bit of time to explore the city, before the crisis. But you would probably have to change stuff then, because it would likely be without much action, considering that Cocoon is, for the most part, a save place. You would just explore how people live their mundane lives. Which would be fine by me, I enjoy that stuff, but considering how people react to the start of, say DQ VII, or slow starts in general, that wouldn't go over well. Cocoon is a save place, on the whole. You wouldn't get much action. Or you would, but than you wouldn't explore what makes it Cocoon.
Considering how people, especially back then, loved chapter 13, the effect you describe (from leaving Midgar and exploring the world) totally happened in XIII. You are constantly running through what are effectively corridors, it's all extremely linear, you are always on the run. And then you get to Pulse. For me, it totally worked. The group seems more relaxed, you can take your time, no one is hunting you for the first time, since the beginning of the game. You can do sidequests, if you want. You have a semi-big field to run around in (which, granted, doesn't have much in it besides hunts, but still, it's not a corridor). The effect absolutely happens, just in a different way. You are finally free, at least way more than you were ever before.
I do agree, that VII worked even better. But this says more about how good VII is, and less about XIII. For me, it worked very well. And it clearly did for a ton of other people.
Again, I understand that the game is messy and far from perfect. I just disagree, that it's that bad.