What's really the point of Kleptomancy, though?
Kleptomancy is for sure a unique rune in many regards and can be loads of fun to play, but from a design/balance perspective, what does it really to the game? It just seems like an RNG based gimmick of a rune that no champion would legitimately take unless they abused the hell out of it (ezreal, GP for example.) Champions with on hit procs on spells are the only ones who take it, and they have plenty of other options without it. It's fun for sure to have 5 potions going at once playing ezreal, but as far as game balancing goes, an RNG based gimmick has no place in this game as one of the 15 keystone runes. IMO, there's just no place/reason for Kleptomancy to exist.
