Sure, good suggestion. Also, don't forget about the ranged slot, which has a very small number of tank items available for it; this could use the same treatment.
But I personally wouldn't stop at just revamping tank weapon itemization. There are a few other niche weapon types that could be rolled into a broader category to further streamline the loot tables. Physical-DPS staves, magic-DPS shields, healing wands, etc. are the types of items that get sharded frequently, because of their narrow focus.
One common suggestion is to find a way to have magic-DPS characters better share itemization with healing characters (convert +hit to +mp5s, or vice-versa). That would work well for Priests, Druids, and Shamans, but Paladins might need some other approach; there isn't a supported nuke spec for them.
The devs have already taken steps to move many of the idols out of loot tables and onto Emblem vendors, so that's a start on simplifying things a bit.
This also ties into the calls to streamline the 11 different armor types that can drop. All 4 types of healing armor are very particular to their tailored class, as is the leather and mail magic-DPS armor.
My rough armor chart from when this came up in a discussion elsewhere:
A list of gear types, and which classes want them.
An 'x' indicates the planned classes, while a '-' indicates an
unplanned class that might still use the item.
Armor Type Total DK Druid Hunter Mage Pal Priest Rogue Shaman Wlock Warr
==================== ====== ====== ====== ====== ====== ====== ====== ====== ====== ====== ======
Plate Phys DPS 3 x x x
Plate Tank 3 x x x
Plate Healer 1 x
Mail Phys DPS 2 x x
Mail Magic DPS 1 x
Mail Healer 1(1) - x
Leather Phys DPS 2(4) - x - x - -
Leather Magic DPS 1(1) x x
Leather Healer 1 x
Cloth Magic DPS 3(2) x x x x x
Cloth Healer 1(1) x x