It's not even that long...
Why a trellium spike? I don't get the point of this.
Have you read WaT?
What about the Aethers? Also, I disagree with your interpretation of Shardic intervention. Intervention implies direct action. Using investiture is not Shardic intervention any more than stealing a fighter jet and shooting someone is intervention by the United States.
Well, Adonalsium isn't really a shard, if you're going to be semantic about it.
You're not being pedantic about intervention. That's just not what it means.
I don't understand your "c-x" notation. What does this mean?
Why? Rashek was a savant.
I don't think you know what Trellium does. That was only for individuals already spiked to be protected from Harmony. Also, I suspect they were controllable (or at least influenced) by Autonomy.
At its greatest potential, this is just a gun that hits really hard. Useless when your opponents can move at supersonic speeds.
Edit: also, the explosion was more due to the fact that it was a Fused with a gemheart. Most people don't have a gemheart.
Are you sure that you have read WaT?
WaT spoilers, because you clearly haven't read WaT.
You haven't even mentioned Heralds, Elantrians, dragons, etc.