Wäre Maelstrom nicht broken in dota 2 wäre es ein op item auf ES.
War in Dota 1 nicht sobuild 6 maelstroms, attacks won't proc chain lightning until first lightning finishes traveling (proccing on almost every attack for 1 target, very rarely if it hits a lot of targets becaus e of slow traveling). Even though stacking maelstroms is somewhat weird, that happens with 1 maelstrom too, effectively reducing chances of chain lightning.