Blade of Ruined King range
I think BoRK is crucial on Kog'Maw but the range for it is pretty bad. I try to distance 710 AA range from anything whether that be team fights of csing so when it comes time to activate BoRK I find myself walking towards what I want to BoRK since it's 500. Right now it's even more dangerous to get near anything as Kog'Maw since he is squishy throughout the course of the game.
My question is why BoRK costs more compared to Hextech Gunblade when Hextech provides a better slow, longer range (700), and a reliable nuke (active). BoRK slow is pretty much negligible with the several forms of gap close available for most champions.
TL;DR : BoRK range seems to favor sticking/engaging on something more than disengage. It's really hard to reliably get away with BoRK slow and E as Koggy