As more expansions come out for Imperial assault more items cards will be released. It seems like this could seriously dilute the decks. Now obviously they're making at least some redundancy but what about items with unique effects like the disruption cell? It seems to me that there are three courses of action FFG could take in this regards.

a) Not worry about it.

b) Add a "build item decks" stage to the campaign setup (can anyone confirm that they haven't added this in Twin Shadows?)

c) Print duplicates of some item cards among new expansions.

Thoughts?

Or the people playing the game can just solve it themselves and put whatever cards they want in the shop and take out whatever cards they don't want in the shop.

A big part of a campaign is the items you draw/buy. I don't like the min/maxing aspect that comes with knowing "after this mission I can buy the xx-gun, so I wont spend cash here". By have a greater assortment of possible item draws you make players weight their desicion making even more. "Well, this gun looks good, but after next mission we get tier II items". It makes for more interesting choices and a more varied gameplay when characters dont always build the same way

I certainly don't see a problem. As said, it leads to more diversity. The fact you increasingly won't be able to go "Well, there is a good chance that next time I will get x item means I won't bother this time" is a good thing in my mind (you still will have the incentive to hold off if you are about to go up a tier of items). Yes, you will sometimes miss out on the more unique items, but that just leads to different play-through experiences, which is also good.