WH40K is orks, WHFB is orcs. Also, Warcraft orcs ARE Warhammer orcs, Blizzard copied them (Warcraft1 was supposed to be a WH game). And they look cartoonish because that's Blizzard's design style (I'd say it's retarded, but to each his own).
And srsly, comparing juvenile Warcraft lore to LOTR??