Preface: Metacommands are used in this specification. The way they are mapped on the real wield syntax is another matter and it is not considered here.
Also, I don't expect that you will throw away anything that is already written (I'm a programmer myself, hehe) and will immedately start implementation of this specification. However, it may still be a good decision, though ANSI standards tend to be never fully implemeted.
After all, Zulg, you've asked players' opinion so you can only blame yourself

Purpose: Design very predicatble wield behaviour with well defined results. Consider held items, wand, weapons and shields using the same approach. Keep the whole thing simple and flexible at the same time.

Wield metacommands:
primary <one-handed weapon or two-handed weapon>- Wield an object in the primary hand or two-handed weapon in both hands for non-giants.
offhand <one-handed item> - Wield an object in offhand.
both <two-handed weapon> - Wield two-handed weapon. This command works with both slots. For everybody except giants it will be equivalent of using primary command on a two-handed weapon. For giants: primary two-handed wields the weapon into the primary slot while this command force-wields this weapon as two-handed.
remprimary - Remove your primary weapon. No parameters. Perhaps should work even if you are blind.
remoffhand - Remove offhand.
remboth - Remove all wielded items. Similar to "throwdown".

Possible outcomes:
Every command produces one of two possible results: success or failure.
Success:
For wielding one-handed items: (primary for a one-handed weapon and also two-handed wepon for giants or offhand for a one-handed item) an item, specified as a parameter is put into the pointed slot. The item that previusly was there is removed. Other slot is not touched. Note: primary and offhand commands consider a two-handed weapon as one-handed for giants.
For wielding two-handed weapons: (both command for giants, primary or both commands for other races) A weapon is wielded as two-handed and autoremoves any items that were held in both slots.
Remove one-handed items: (remprimary for a one-handed weapon remoffhand for a one-handed item) Emptifies the specified slot.
Remove two-handed items: (remprimary or remoffhand while wielding a two-handed weapon) Emptifies both slots.
Remove all items: (remboth) Emptifies both slots. Works for one-handed items and two-handed weapons.
Failure:
It's guaranteed that nothing changes in the current status of both slots. No items removed, nothing is swapped.

Reasons for wield failures:
Everything that would lead to the inconsistent slot combination or can't be performed because of other reasons.
Possible reasons for wield failure include but not limited to:
- inconsistent slot combination.
- weight.
- race/class/alignment restrictions.
- blindness (potions can still be wielded).
- a cursed weapon that already occupy the specified slot.
- broken arms.


Possible future changes:
Combo command.
This command allows combine several atomic comand and execute them as a whole in one pulse.
For example:
Combo remboth, primary sword, offhand dagger - In one pulse removes all weapons and duel-wield sword/dagger combination. The combo command is succesful if any of atomic command is successful. In other case, the combo comand fails and nothing is changed.
Notice: that having a such command makes autoreplacement feature of atomic commands obsolete because it costs "nothing" to remboth before wielding new items.
However that may lead to some balance changes and make some legacies less powerful so it should be thoroughly considered.