I have to agree with L9753. The speed and accuracy of your Armiger has to be improved, especially the speed.
Please find below the stats of my two Armigers (one is in Destroy gear for Doom Tower). I have to admit that some of my artifacts have to be replaced. I had to use for one of my Armigers an ATK amulett. It was the only with accuracy substat to improve my accurcay to 200 points.
My Armigers are built very bad lol. I built them forever ago and need to regear them. My Crit Rate is around 90% because I wanted Crit Damage gauntlets as well.
The main things you need to build your Armiger with are Speed, Crit Rate, and Accuracy. That allows him to perform his A1, his main ability. Then prioritize Defense so he can survive and hit harder. Last I prioritize Crit Damage for the latter reason of Defense.
You can also build him with HP if you dont want him to be targeted.
I basically had 3 goals with mine, get accuracy over 200 (was aiming for 230), get speed over 190, get crit rate to 100. I gave him gear before masteries (yeah, I know, I know). As it is, he's currently farming masteries with 4 other champs and I only filled out his first 2 rows. The speed over 190 was for the spider but obviously more is better. He does his job currently so I'm not going to regear him anytime soon and he won't be allowed to take gear from any of my other good champs. Still, I'd love to double the crit damage and add 20-30 to the speed.