My new main is a Shiradi Champion Artificer (full fate points) ever since the expansion. I have never seen Shiradi abilities ever proc from my runearm attacks. I tested it when the expansion came out, and I just tested it a few minutes ago to make sure nothing changed since the patch using Lucid Dream and Tira's Splendor.
I wish that Shiradi Abilities did proc and scale from runearm attacks, but this is not the case.
To the OP, I have no gripes about Shiradi Champion for my Artificer. In my opinion, it is the best thing that ever happened for my Artificer. While an Archmage will utilize SC better than my Artificer, Shiradi Champion seems like it was made for the Artificer.
I assure you. You have not seen a fully geared/fated Shiradi Champion Artificer in action.
My Artificer's name is Deathaven on Khyber.