I would like to see them moved to the DMG and even then, creating them should be a challenge.
I also would like to see the magic item based on the character's level, so it gets more powerful with him or her as he or she advances.
There are some things in this list I agree with and some I don't. I'll start off by saying I partially agree with this. I'm not sure that a magic item should always get more powerful based on the character's level without additional input. Some could be automatic, but others I would prefer would not.
Potions, scrolls and even wands should be easy to make, granted wands need a special component (like a healing potion needs a strand of hair from a unicorn's mane...willingly)
I agree with potions and scrolls. Not so much with wands. If they continue to be easy to make (from 3e onward), I would significantly reduce the number of charges they incorporate. 3e's wand of cure light wounds is very helpful, particularly in working against PCs trying to take a night's rest on short but hit-point loss heavy adventuring. But it's probably too cheap for its 50 charges.
Arms and Armor should be rare, but also powerful.
I think the special abilities added to weapons should (if they can be made) require a quest or something challenging, like a flaming sword needing to be dipped in a volcano or breathed on by a dragon meanwhile a holy sword would need to be blessed by a celestial being (or something similar depending on their religion/deity)
I think armor should be similar, or crafted on magical forges what are ALWAYS guarded by mean nasties who love to not stay dead.
Special abilities may be more evocative in this way, but I totally disagree with these items being rare. One bright spot of random treasure generation in 1e/2e was that the most common items were potions, scrolls, and gear of war - arms and armor. 1e explicitly recognized that some classes were more equipment based than others and skewed the random treasure tables to give them more common tools. Wands, by comparison, are substantially rarer than magic weapons and armor. It was one of the balancing factors between fighters, for example, and magic users. And in 3e it was lost, and exacerbated by the addition of the magic item creation feats with their caster level requirements.
Rings should be in circulation, but few should know they are magical (detect magic goes out the window for rings) meanwhile staffs should always look cool, and just by looking at them you should know what they do.
Wondrous items should have their wonder back.
Cursed items should be a much larger fear.
Agree with your points here. Pathfinder injected a way to get a cursed item by blowing your magic crafting roll, but the DCs are set low enough that this is unlikely unless you're deliberately trying to make something without having all of the required components (which can be dispensed with for an increase in the craft DC).
All items should be unique (no more "+1 keen longswords"
Try +1 keen longsword that can detect poison 2/day, it is named "Kingsfriend"
I can see a point for somethings, particularly with extra powers, being unique, but I still think there's a value to having basic pluses as well. Imagine a sword that's a little bit better than a regular one and how valuable it could be. For simplicity, it works really well to just give it a bonus to hit and damage.
One thing I would take a good hard look at, if there's any component of wealth (or even level) inherent in the expectations of what items PCs will have when, is that items that are always useful have more inflated values than ones that are more situational. My classic example is the ring of shooting stars vs ring of protection. The ring of protection is exceptionally useful, nearly all the time, at any value. The ring of shooting stars has several bits of interesting and quirky, but not particularly powerful, utility in various states of darkness. The ring of protection in 3.5 maxes out at +5 to AC at 50,000 gp. The ring of shooting stars is also 50,000 gp, but is nowhere near as generally useful
By comparison, in 1e, the ring of shooting stars was 15,000 gp and rings of protection varied in value between 10,000 gp (for a simple +1 to AC and saves) and 20,000 gp. I would submit that the price of the ring of shooting stars is much better in 1e relative to the value of the ring of protection than in 3.5.