Really? You cite Trickster, Changeling, and Empath as the bad aliens in this set? I felt that each of these was unique and solid. Certainly functional, unlike Visionary or The Claw, which are both easily non-powers for the whole game. But overall, the alien quality in CC was fantastic: Cavalry, Filth, Glutton, Industrialist, Lunatic, Relic, Warhawk, and Xenophile were all amazing additions. I would be more than happy with another expansion of CC's quality.
Somehow, I don't see more tech cards coming in a standard expansion. FFG has appeared fairly consistent in including one unique deck in each game: tech in Base, Rewards in Incursion, and Hazards in Conflict. It would match their other expansion models with other game series to very rarely expand previous expansions. (The negative reaction to support for Cylon leaders in the second BSG expansion would be a solid example.)
On the other hand, if FFG puts out a Miskatonic Horror-esque expansion for Cosmic (ie, an expansion which exclusively expands other expansions), that would be pretty awsome. On last big box to double techs, rewards, hazards, etc. Now, Cosmic would have to be as successful as Arkham Horror to dictate such a fan-pandering expansion, but it would be nice.
The simple counter argument is that Tech was in the FFG base game, so everyone has access to it. My rebuttal to that is that Tech was included as an optional rule which doesn't interact with any other of the module parts of Cosmic. Releasing more Tech cards would be like releasing an expansion for an expansion, pandering to a subset of overall Cosmic players, especially since many people don't play with it. Additionally, some people might not want to spend money on an expansion that they essentially already have; why spend money on new Tech cards when they could be making something else new?
Now, I'll take whatever they put out for a third expansion. Cosmic is probably my favorite board game and I look forward to increased customization through new modules and new aliens. I just don't see more Tech coming out soon. Feel free to quote me if/when I'm wrong.