At least for artifacts, I wouldn't expect it. They're supposed to be one-of-a-kind, a thing of legend - the PC shouldn't realize what he's just put on without magical efforts.

Which is something to be kept in mind for many of these; that the effect itself is noticable doesn't mean that knowledge of that particular magical item's powers is so widespread the PC should immediately realize he's wearing one. But then, for many other magical items, he does. Weird.

This yesterday was tackled with some other issue (forgot the number). The idea is that any item with a variable modifier (e.g. to speed or attribute) doesn't auto-identify. But there was a bug that prevented others from identifying as they should have.

I think this is worthy of another look.

The main problem with current implementation is that the PC can still determine what bonuses are granted, by looking at their stats, putting the item in question on and looking again.
That way you will know instantly whether it has a PV/DV bonus, a to-hit/to-damage modifier, attribute bonuses (or penalties like cold heart).
Instead of having that information in one place, you need to check several screens. These days you can even add a note to the item that tells you what it does.
Wouldn't auto-id be a much better solution here? Come on. There could be at least partial ID that shows PV/DV, hit/damage and attribute modifiers, if not the name.

The only outcome you achieve by not letting those items be equip-ided is forcing the players to search through various menus for the change, equipping and unequipping different items.
It's not intuitive, there is zero added value here, you're only increasing the UI hassle.
I understand that rings/amulets/bracers/gloves etc granting resistances/intrinsics are not auto-ided because the effect is more subtle.
However, anything that changes numbers otherwise easily viewable in inventory or on character tab should auto-id instantly.