MOBA gets my award for worst initialism ever. It's hopelessly meaningless, as it describes everything from WoW to PBEM Chess.
IMO, that's really what makes DOTA/clones uninteresting to me - an interesting and strategic action game saddled with a non-relevant RTS interface.
It's a RTSS Real Time Strategy Shooter sort of thing. It's an FPS game that is sort of like a strategy. Not really any of those, but sort of close.