I would say Litecoin is the best candidate of being a true global cryptocurrency (USD version of a Crypto). It has huge capacity, its a true cryptocurrency (not a dapp or ico platform), it has antispam tech inbuilt (so no one can spam it like they did on Bitcoin), it can scale on a near infinite scale, the west and the east love it, its stable (unless its climbing in value),  Litecoin is ready to go!  All it needs now is more adoption.