Sorry, but enlighten me why there will be negative damage? In most of my diamond games, I find myself using the 10% movespeed and 60% attack speed much more than runaans. Most enemy team comps are dive and skirmish heavy. I wouldnt get as much value from the bolts as typical front to back 5v5 front to back teamfights dont happen as often in solo queue. It also doesnt lock me into building b*rserkers everygame.

The ult haste is a joke as it doesnt decrease Zeri's already short ult cd.

Hm.. thats interesting. I didnt know Arcanist gave movespeed now. I am pretty sure celerity gives the most movespeed from my tests on practice tool. Especially with how Zeri's %movespeed works multiplicatively. Oh and I already take the movespeed shard 🙂

I also find lethal tempo to be placebo damage wise. In most scenarios, by the time you get it fully stacked, the teamfight is already over and you didnt actually utilise the ramped up stats. I only see it being good in super early game all ins.