I'll start from what annoys me most:
I am not sure if this is WAI or is it a bug, but currently, when you want to shoot your rune arm you have to actualy aim at the target. Needless to say that you don't need to do that with spells or any ranged attacks, just with rune arms. It really makes the rune arm not fun to use, the energy you need to put for a single shot is not worth using it at all.
So my first suggestion: Make run arm target like any other ranged\spell. I suggest make some of the rune arm projectiles chase the targets much like the spell Force Missile, and some just shoot in the target's direction like fireball (Target can manually avoid being hit.)
Repeater crossbow reload: Currently, one click will fire the bolts, second click will reload it (Unless you hold the fire button, which will fire->reload->fire->repeat).
My suggestoin: Make it automatically reload after every shot.
Artificer prestiege enhancement:
Currently there is only one. This isn't a big detailed suggestion, but for tier2 and 3 I would like to see improved Endless Fusillade. Maybe make it 8 seconds at tier2, 10 seconds at tier3. Also, some boots to UMD (+1 at tier 2, +2 at tier 3) and a little better save against traps.
Score board doesn't matter a lot, but it's still a bit annoying that the kills from Flame Turrent count as Misadventure. So yeah, it's a construct, and it can be killed, but come on, I created it! It doesn't have its own will like ohter summons, it's stationary just like firewall, ice storm etc.
To sum it up:
#1: Rune arm target like spells\ranged, not having to actualy aim at the target.
#2: Crossbow auto reload after each shot without having to click again.
#3: Idea for Artificer prestiege tier2 and 3.
#4: Flame turret kills don't count as misadventure
Thoughts?