their shields are weaker and thus needs more then average amount of soldier to keep producing a fleet
That actually aint true, the thing is that u mean bugs shields are weak, simply because we have seen very little of other ships so noone can really say about other

Now about the ketrazel, as far as I know u cannot add new resources to A2, only modify the old existing ones, now my question how many resources were there in A2, cause they have already added 5 different resources(dil, tri, crew, supplies, credits) so I dont really think they have much more to work with :S