So, here is my two cent after clarification.
So, just to make sure, I like both.
Coordination would meld the arts more, either letting the arts tag each other , so they are more effective crowd controls or just able to benefit from the other arts stuff.
Personally, I like this, it fits with the scout theme LQ usually have, and would give us a more cohesive view of the battles, not to mention that our summons would be more flexible in their tools, as described by the arts.
It could, also, give the winged bear summon people wanted from complexity, before clarification.
Meanwhile
Complexity would gives finer control, like being a director in a movie or dance instructor, with our constructs being able to make mundane lives easier..... (Just don't let CRX find out that we passed the paperwork to them or she will give us more work

)
Basically we can use our constructs better, both in and out of combat.
Might get some fun scenes of it as well, as LQ tries to debug her programmed constructs lol.
But the real treasure here is that our constructs can act without our input.
Guard CRX, evacuate the wounded, fetch loot for momma, play with the mortals.
Both are great upgrades, and there is nothing saying we can't take up the other later on.
Still, I stay with coordination because it let us do telepresence earlier, like at the end of revelry, though it's only sensory input for now.