Is Luna moonfang the greatest hero in DOTA?

No, Luna Moonfang is not the greatest hero in DotA. She's a pretty weak hero with short range, and most intelligent heroes will be able to do large amounts of damage with their spells to her. Her damage is also weak, and that makes farming hard as killing creeps will be more difficult. While she does make up for her weak health and damage with a few awesome spells, her lack of mana is also a problem, leaving her as a one-shot cannon until she gets a bunch of items.