At lower levels, items are relevant because they are a reliable source of stats, consistently giving (+) stats as you progress. But, like leapinglizard said, at higher levels they become increasingly irrelevant. With that said, I don't think we should remove items from missions all together. But I do think they should change the item system.
Currently, mission zones give items corresponding to your level, as we collect better items then those extra items we find become coins and we need to level up to get even better items. And with the soft cap it becomes time consuming to achieve this. Furthermore, since zones don't give set items, it becomes less likely to find decent items. Whereas special missions are better than zones since they occasionally give (+) stat items (I usually get enhanced weapons from here), 5% set items, and (+) missiles.
One solution would be to buff the items coin value near or even higher than regular coin missions.
Another solution would be to have specific stat items in each zone with better stats or more enhanced items (missiles, sets, etc.) in the higher level zones. Although I don't agree with having set items in regular zone missions. It also would mean the lower level zones become worth less coins, stats, etc. and may cause others to avoid these zones leaving us with less apparent mission options.
One other solution I will suggest is scaling items to items we already have. For example:
- a common item will scale (+0.001 to +0.01) to a common item of the same type
- a rare item will scale (+0.001 to +0.01) to a rare item of the same type
- an epic item will scale (+0.001 to +0.01) to an epic item of the same type
- a rare item will scale (+0.01 to +0.025) to a common item of the same type
- an epic item will scale (+0.01 to +0.025) to a rare item of the same type
- an epic item will scale (+0.025 to +0.05) to a common item of the same type
Although there may be balancing issues if someone decides to grind for items all day every day.
These are just a few of the solutions I thought of. Obviously, they are not the best solutions; and they are not the only solutions. But I do think they should change the item system somehow.