This is a hot topic.
I know a small part of this has been addressed before, with the missiles of *foo* slaying and it worked marvelously, though many hoped it would have been extended to all missiles.
Rightly so.

Now, here's a very brief excerpt from a pile of items weighing around 40k stones, collected in BDC:

4 robes, 6 if we count the clean one and the black one.
None stacking because of tiny little differences that bring absolutely nothing to the table.
I'm not even asking about the [0, -1] kind because I can't imagine how a piece of cloth can actually lower protection value.
Would it be so bad to fix *all* random robes to have [+1, 0]?

It's just a start.
There are two ring mails there which have the same protection and defense values of [-1, +3].
However they *slightly* differently affect melee and missile attacks.
Why? What's the point?
The difference is virtually non-existent.
It's non-existent even for starting characters that have enough to-hit at level 1 to not give a flying F about that -1 or 0.
The only outcome of that variation is extra inventory slots used and extra time needed to manage that.
I advocate to set that chance to hit to fixed values of (-1, -1).

Some armors notably affect said chance to hit in a more significant way, like full plate mails and plate mails in general.
That's fine, as long as the values remain fixed within that one item class, i.e. same for all adamantium plate mails, all mithril chain mails etc.

I know that you can roll a character like wizard or mindcrafter which starts with just a robe and a pair of boots in terms of armor.
Occasionally, that robe could be as high a [0, +4], which makes a big difference in the early game, especially if footwear also grants some PV.
Paladins and CKs especially can vary greatly in how much starting PV they have, which is ok I guess.
So let it stay in that case - items generated along with the PC could have that variety because they are just one of a kind.
It adds flavor and gives an early advantage on some lucky character rolls.

All of the above can be extended to virtually every piece of armor - helms, gauntlets, boots, shields, cloaks, etc., but also to weapons and especially regular missiles.
The variety could stay as it is for items with prefixes/suffixes because let's be honest - those are only desirable for the affixes, not the pv/dv or minor chance to hit modifiers.

Diversity is nice and I like it but only when it achieves something.
The only thing achieved here is extra pages in the inventory that the PC has to browse, and several more clicks when dropping or selling items, nothing else.

Here's a nod towards auricbond and gr3ybird who have reminded me I wanted to post this a long time ago.
Keep up the good work, I love arguing about tiny details with you guys ;)

Still on the wishlist: All item categories should sort entries alphabetically. That would be amazing. Perhaps another RFE.