Complex sentence: In 2011, The Rock's return generated a lot of buzz, an average of 4.7 million people watched that episode of "Raw", but 7.4 million tuned in just during The Rock's promo.
Split into simpler sentences: In 2011, The Rock's return generated a lot of interest. An average of 4.7 million people watched that episode of "Raw", with 7.4 million tuning in during The Rock's promo.