D&D 5E (2024) So the Armorer still need be Wearing before Don his armor.

[pukunui]

I think the intent is clear, even if the wording is off. Once it is arcane armour you can don/doff as it as an action.

I think the only benefit that really needs to be "while wearing the armor only" is the spellcasting focus one. You shouldn't be able to use your armor as a focus if it's sitting in a heap out of reach. Also, the "no Strength requirement" benefit only comes into play while you're wearing it. It's irrelevant when you're not. So yeah, the wording is poor, but the intent is clear.

 

[Misanthrope Prime]

how do you put on armor you're already wearing?

Maybe you're only wearing part of it? Kind of like Kamen Rider's armor can come out of his belt.

 

[Stormonu]

I think the intent is clear, even if the wording is off. Once it is arcane armour you can don/doff as it as an action.

The intent is certainly clear - put it on or take it off in one action, but they really ought to fix the wording for later printings/in beyond.

 

[TiQuinn]

the rule, as written, is that while wearing your armor you can don (put it on) as an action. But you can't wear armor you don't have on already.

Yes, but is this anything more than concern over an editing error?

 

[Sorinth]

Isn't this why the books say don't take the rules too literally and try to parse the language so that it goes against the natural language/common sense reading.

Like sure it's somewhat lazy to not correct this type of thing as part of an edition update after similar language has been pointed out, but really who cares. These types of things are bottom of the priority list.