I didn't really read the whole thread, so I'll just share my thoughts on the matter.
In my games, nobody has to worry about finding or identifying magic items. Most magic items are obviously magical and/or valuable, whether it's a sword with a leering vampire's face on the hilt or an axe with gold filigree scrollwork down the edges or a silver-embroidered robe that shimmers like water in the torchlight. They don't necessarily glow or anything, but they're clearly above and beyond the level of average weaponsmithing. Even items that aren't necessarily pretty are usually distinctive -- a pair of Gloves of Ogre Power are made with truly massive studs and such that will naturally draw the eye. But even if they're not visually startling, handling magic items immediately informs you that they're magic. Maybe it's tingle when you touch them or just an ineffable sense of power, but you'll just know. And I usually just go ahead and tell the players what it is, too. If they find a vampiric longsword, there's no clear benefit to me witholding that information, so I don't.
That's what I do, and I've never had a problem -- in fact, there's nothing in the book that suggests this is not the default assumption. None of the uses of Arcana have anything to do with identifying items! You can identify conjurations, zones, rituals, and "magical effects" that are explicitly not powers, rituals, or items. Nothing said about IDing items, there. The last use is "detect magic", but even then the benefit is really detecting magic at range and seeing through walls with it.
I use Detect Magic sort of like healing surges. If you want to figure out what magic items are involved in a battle, you use Arcana and so forth and you learn that the leader's axe is magical and probably some basic info about what it does (for example "it drains life from felled foes to bolster the wielder", but not "he gains 10 temporary HP when he drops an enemy"). After the guy's dead and you're handling his axe, no check is necessary to figure out that the axe is magic and what it does.
So on that level, my party never just "walks by" a magic item by accident.
Now, sometimes they avoid an encounter entirely, or defeat it in a non-combat fashion, or some similar thing that aces them out of getting the loot. In that case, I usually just handle it on the fly:
The big question is: Did they defeat the encounter? If they got past it with skills or talking, or if they drove the enemy into retreat without actually slaying them all, they still defeated the encounter. They earned the treasure, so I'll just add it to the reward for a later encounter. I tend to work on a feast-and-famine reward structure anyway, so they go through several encounters with little or no reward and then find a treasure vault or hoard later that adds up to the same amount. (It's more fun to find two cool items and thousands of GP than to get that same quantity piecemealed out over a half-dozen fights!)
If they didn't defeat the encounter -- for example, they just didn't go into that room or something -- they just miss out on that treasure. If that fight's reward was going to go into a hoard, I deduct that value. It usually works just fine, because they also missed out on that XP and are thus going to need one extra fight to level up anyway.
There are cases where that causes issues, like if they walk right past a fight where the bad guy has a cool weapon or item that's part of the encounter (rather than inert treasure); but if that happens I'll either try to throw that enemy in later somewhere else or just give up and give them the item as part of a hoard, depending on the situation. Sometimes I can just move the guy to a different location and make the PCs fight him anyway, or have them face him on the road later (sometimes with a little species swapping) as a bandit-king or some such thing who wants what they found.
Oh, I should mention, it's not usually possible to miss a hoard. I put those in battles that the PCs can't avoid, either because it's the boss battle they have to do to finish the adventure, or because it's on the way to that final battle and they have no choice but to go through it. Or I'll have another NPC tell them where the treasure is, which is usually plenty of motivation for my group to go find it.
In my games, nobody has to worry about finding or identifying magic items. Most magic items are obviously magical and/or valuable, whether it's a sword with a leering vampire's face on the hilt or an axe with gold filigree scrollwork down the edges or a silver-embroidered robe that shimmers like water in the torchlight. They don't necessarily glow or anything, but they're clearly above and beyond the level of average weaponsmithing. Even items that aren't necessarily pretty are usually distinctive -- a pair of Gloves of Ogre Power are made with truly massive studs and such that will naturally draw the eye. But even if they're not visually startling, handling magic items immediately informs you that they're magic. Maybe it's tingle when you touch them or just an ineffable sense of power, but you'll just know. And I usually just go ahead and tell the players what it is, too. If they find a vampiric longsword, there's no clear benefit to me witholding that information, so I don't.
That's what I do, and I've never had a problem -- in fact, there's nothing in the book that suggests this is not the default assumption. None of the uses of Arcana have anything to do with identifying items! You can identify conjurations, zones, rituals, and "magical effects" that are explicitly not powers, rituals, or items. Nothing said about IDing items, there. The last use is "detect magic", but even then the benefit is really detecting magic at range and seeing through walls with it.
I use Detect Magic sort of like healing surges. If you want to figure out what magic items are involved in a battle, you use Arcana and so forth and you learn that the leader's axe is magical and probably some basic info about what it does (for example "it drains life from felled foes to bolster the wielder", but not "he gains 10 temporary HP when he drops an enemy"). After the guy's dead and you're handling his axe, no check is necessary to figure out that the axe is magic and what it does.
So on that level, my party never just "walks by" a magic item by accident.
Now, sometimes they avoid an encounter entirely, or defeat it in a non-combat fashion, or some similar thing that aces them out of getting the loot. In that case, I usually just handle it on the fly:
The big question is: Did they defeat the encounter? If they got past it with skills or talking, or if they drove the enemy into retreat without actually slaying them all, they still defeated the encounter. They earned the treasure, so I'll just add it to the reward for a later encounter. I tend to work on a feast-and-famine reward structure anyway, so they go through several encounters with little or no reward and then find a treasure vault or hoard later that adds up to the same amount. (It's more fun to find two cool items and thousands of GP than to get that same quantity piecemealed out over a half-dozen fights!)
If they didn't defeat the encounter -- for example, they just didn't go into that room or something -- they just miss out on that treasure. If that fight's reward was going to go into a hoard, I deduct that value. It usually works just fine, because they also missed out on that XP and are thus going to need one extra fight to level up anyway.
There are cases where that causes issues, like if they walk right past a fight where the bad guy has a cool weapon or item that's part of the encounter (rather than inert treasure); but if that happens I'll either try to throw that enemy in later somewhere else or just give up and give them the item as part of a hoard, depending on the situation. Sometimes I can just move the guy to a different location and make the PCs fight him anyway, or have them face him on the road later (sometimes with a little species swapping) as a bandit-king or some such thing who wants what they found.
Oh, I should mention, it's not usually possible to miss a hoard. I put those in battles that the PCs can't avoid, either because it's the boss battle they have to do to finish the adventure, or because it's on the way to that final battle and they have no choice but to go through it. Or I'll have another NPC tell them where the treasure is, which is usually plenty of motivation for my group to go find it.