- Attunement is a good idea in theory, but they need to work on the implementation. Right now it's just a 10 minute cooldown on swapping items, and that just feels like a pointless nuisance. Also, I think more items should require attunement.
Agree completely. I suggested in the other thread about 1 day for attunement, and to replace the attunement ritual (sounds a bit too cliche to me) with just the idea that you have to use the item or at least wear it in order to attune, and that means you have to already "de-attune" or at least not use one of your other attuned items in the meantime.
But it depends on what are the purposes of attunement, which can be different... I think with 1 whole day required (coupled with the pre-emptive de-attuning with another item) I would achieve the purpose of making swapping those major items carry a cost: not a huge cost, just the fact that you cannot do it in the middle of a day, and for 24 hours you'll be limited to only those features that work regardless of attunement.
But again, your purpose might be totally different. What do you think?
- They really need to make it so that bonuses from magic items do not stack with each other. You can get an AC in the mid to high 20s just with the items in the playtest packet since there's no general rule preventing magic armor, ioun stones, defender swords, etc. etc. etc. from stacking. Only the ring of protection specifically has this restriciton. It needs to be a general rule.
I agree again. It would match with the bounded accuracy concept.
Perhaps a middle ground could be found in typed bonuses, but to keep bounded accuracy they would need to be very few types, maybe only deflection bonus to AC and natural armor bonus to AC? It might not even be needed tho.
- Some items are just plain better than others. Compare, for example, the Pearly White Spindle Ioun Stone (a legendary item) to a Ring of Regeneration (a very rare item). The ioun stone heals you a pitiful 1 hp per hour. The ring heals you 1d6 hp every 10 minutes (making it heal you on average 21 times faster than the ioun stone). Plus, the ring regenerates lost limbs. I realize the ring requires attunement, but so what? It's an entire rarity category lower. An attunement requirement doesn't justify one item being 20+ times as powerful as another.
I don't see this as a problem if we are far from the "magic shopping" general approach to magic items of 3ed. In that edition, every item has a market price, and the system assumes your have magic equipment to match your level. This kind of made 3ed assume the default that the magic item list of DMG is a shopping list, and that a PC is entitled to find what he wants for sale, as long as he pays the GP price...
But the default approach of 5e is more like "whatever the adventure brings you". In this case, the ioun stone is totally useful for a DM who doesn't want rings of regeneration in the campaign! With the 3ed mindset, the ioun stone inferiority would need to be compensated with a lower price. With the 5ed mindset, ioun stones and rings of regeneration can be equally "good" tools for a campaign.
- Items that boost stats, especially those that raise it to a set value rather than granting a bonus (allowing people to completely ignore low natural ability scores) need to DIAF.
I am fine with those items, exactly because of the 5e mindset above. They're not a big deal if the default is that they are just tools in the hands of the DM and the players to shape a campaign.
- The secrets on some of the items, particularly the Ring of Feather Falling, seem to be there for no other reason than to give the DM license to suddenly kill off a PC. Not cool.
I don't think that's reason, but rather just spicing up the description and add a little thrill or unpredictability. Notice that it even says that only some rings have such property, i.e. the DM doesn't even need to say she is house-ruling RoFF, just let the players only find those without faults.
- Some items are overpowered (this is to be expected in a playtest). A good example is the Potion of Speed, which makes even the overpowered 3.0 haste spell look modest in comparison.
I love that potion.

More usable in the game than Haste since it gives you 2 turns at different times instead of a double-sized turn. Only problem is the question whether you should count durations (of spells cast on you and spells you cast) normally or if you should speed them up too.
But once again, the problem is in the default mindset used in a campaign. If you let the PC buy (or brew) potions of speed at will, then it's not going to work. It will be overpowered as you say. The only way to keep it under check, would be to set an outrageous price.
To me the problem is viceversa, that after a few years of playing with the 3ed mindset, I got bored and pissed off by the idea, and most 3ed magic items are designed to be quite flat and boring because they're assumed to be used in that mindset. An item such as potion of speed is something I would definitely want in my campaign instead, but I'll just choose to use it as rarely as I feel necessary to keep it special and not overpowered. I mean, it's still overpowered but just for 1 minute, and if it kills the fun once, you won't see another for the rest of the campaign.