I can see where you are coming from here - but most of these items are simply hidden in obscure places and if you didn't already know about them and go looking, you would be hardly likely to find them.
It is not like they were a bonus for exploring the maps or anything. The classic examples being the +1 Ring of Protection, the Ring of Wizardry, and the Ankheg Plate Mail - these were just hidden in pointless spots, and the only way to spot them would be if you moved your mouse across them and found a container is highlighted.
It would have been better if there were clues to the locations of such items - at the very least, it would give you some sense of why such precious items are just lying around waiting to be picked up by your party if they stumble on them. They are just there though - and most people would only have known about them from a walkthrough.
The inconsistencies are also a minor niggle, but then if the game had something in all the containers, there is a risk that the game might become unbalanced. Sure, there are loads of boxes and crates in a warehouse, for example, but you can only open and explore a few of them. This is fine with me, but having to find which boxes you can loot by moving your mouse over everything is just annoying.
While I am not adverse to this method of gaming, I would hardly call it tactical. This is more trial and error, and is a very crude method for playing the game. This is particularly important when, in most cases, you won't actually have any idea of the creatures you will be facing until you face them. Of course, being low level, this is rarely important because the creatures generally don't have that much variety, so you can brute force your way through things, but pausing the game for inventory swap outs would have reflected tabletop play better.
Having played through the entire game now and having started on BG2 I think I agree with you a bit, though it only became a real issue for me after reaching Baldur's Gate itself. I'm still not too keen on having Tab show every interactive thing on screen though because it doesn't feel like I'm exploring a medieval/fantasy world when I'm just hitting the "scan" button. I would rather have more subtle visual clues on interactive items/containers (sparkles, different colours, asymmetric placement etc.). Either that or they could be highlighted when your party moves closer, like with secret doors but without the chance of failure. BG2 seems better about examinable
objects though, in that there are more of them and they tend to stand out well. BG1 sometimes had signposts out of sight, beneath roofs.
We're on the same page about stuff like the ring of wizardry. I actually found the Ankheg plate on my own back then but yeah, it was pure luck.
@Tactics/pause during inventory screen: The trial & error is still there with a paused inventory screen, it just reduces the number of times you'll have to reload your save when you can more easily react properly to whatever they're doing. I think to make battles more tactical (or is it strategic?) there would have to be some sort of scan ability/spell that lets you see enemy gear and spells, but at least you can scout ahead and get a general idea of what you're facing, which also becomes easier to predict as the game goes on. I still used potions and scrolls a lot despite the pause function (or the belt function) not being there though.
In case you didn't know (and I discovered this after my post), playing BG1 in multiplayer will keep the game paused when at the inventory screen.