I dunno if I would consider Wiley as the creator of Grime but he is a great producer. As an MC ? Probably not, but if you listen to his during the Pay As U Go days, he had the charisma to be one of the best Garage MCs. Some people would trace the root of Grime with the So Solid Crew or The Heartless Crew. During the late 90s, Garage started to transform from it's House origins to a Hip-Hop and Drum and Ba** sound.
But back to Wiley as an MC, if he was to battle any American Hip Hop artist, he would probably win.