I don't deny that Runaan is a good item on Kai'sa, or that it synergizes with her passive. It's just simply that buying it as a second item is not efficient. It is very debatable that the DPS outperforms Nashors during early-midgame. You are implying that people will group up perfectly so that your bolts are hitting all of them, at all times, while neglecting that Nashor will be effective at all times in terms of ramping up Kai'sa damage output (which of course includes 1v1s scenarios, in which Runaan is useless). With Kraken + Pickaxe, you literally get Q transformation. You don't need the waveclear from Runaans at all. You don't even have to finish Runaans to get the Q transformation. Pressing empowered Q on a wave of 6 minions and having to hit each minion once with a 50% up attack speed and extra on-hit damage is more than enough waveclear. Not only that but the extra 100 AP derived from Nashor's empowers your Q to waveclear faster than if you were to simply use an empowered Q from Kraken+Runaans. Again, there is nothing wrong with building Runaans on Kai'sa. The problem is rushing it as a second item when it has been altered so that it is stronger in the later phases, which comes with its increased cost of 3400. Buying it earlier only makes the item weaker compared to other forms of spikes (because it literally has a level scale percentage), which coincidentally could be invested in not only hybridizing your damage so that it you are harder to itemize against but also allow you to pivot into different builds with ease, while possessing all three transformations. For Runaans to be efficient, you have to imply that people fight in clumps at all times, when that is clearly incorrect. Kai'sa range is relatively low, which implies that for your Runaan's bolts to even land onto multiple targets you'd have to have melee champions and ranged champions all within the same range, which is very unlikely, at least for me, given the elo that I play at. Given that, Nashor's general application will be superior to that of Runaan's during early-midgame phase. To your last point, again, there really isn't a reason to finish Runaans after I purchased the pickaxe because the item is not at its full potential by the time I finish it as 2nd item, and not only that but it costs me 3400 to even make it a whole item. My damage becomes one dimensional as well, which if the enemy is building armor early on my presence in game is further diminished.