I think Arti could use a few smallish tweaks to its enhancement trees to bring it up to date just a teeny bit more and undo some of the damage that Inquisitive did to repeaters as a functional build. Here's some suggestions I came up with:
Battle Engineer
Make Runearm Stable Charge Tiers an inherent part of higher-level runearms instead of requiring you to take multiple cores in Battle Engineer to get them.
Remove the "when your runearm is charged it gives you more spellpower" from BE and move it to Arcanotechnician.
Give a damage imbue similar to Eldritch Knight that only works with the main Battle Engineer weapons
Add 2 weapon buffs to the tree: one that makes your weapons immune to ooze damage and one that gives ghost touch. Also, add int-to-hit and int-to damage and a know-the-angles stance natively to the tree so you're not reliant on Harper to make your class functional. Tie it to the BE weapon selection so it doesn't become too general.
Arcanotechnician
IMMUNITY. BYPASS. If you want, make it so you have to hit it with your runearm to turn off their electrical immunity briefly.
Replace Palliative Admixture entirely with an ability that isn't godawful. My suggestion would be an Electric Loop SLA.
Thaumaturgical Battery is also garbage. Recommend replacing it with Lightning Bolt SLA and replacing Lightning Bolt in core 12 spot with Ball Lightning.
The lightning spells in Arti need a pass similar to what was done with wizard/sorcerer spells. Their damage is just too low.
Renegade Mastermaker
Need something to replace Conjure Component. I recommend an ability that makes your runearm count as a shield for feats and abilities.
Reconstruct SLA should only cost 1 point per rank, not 2.