Before I start, I just want to point out that this is based on theorycrafting, not actual in-game testing.
Fjola Lightbane drops the Diplomat: http://www.wowhead.com/?item=47740
Anub'Arak drops Baelgun's Heavy Crossbow: http://www.wowhead.com/?item=47741
(Both alliance versions, Horde available also)
Now, the Diplomat has +15 hit while the Heavy Crossbow has no hit and also a slower attack speed, which is usually beneficial to hunters (2.9 vs 2.8 ).
Common sense would tell me that if I needed the hit, the gun would be preferable but if i was already at the hit cap or higher, the Crossbow would be preferable....wrong! The gun is better in all circumstances!
A strange result and I've also tested in SV/MM specs and the same is true, so if like me you have both, you can safely DE that Crossbow.
[EDITED: Added a space between 2.8 and the ")" otherwise this happens: 2.8) ]