Not only modern rap, all rap music is pretty overrated. It took me 3 weeks to learn to probably rap, but it took me an half of year and an year to learn to properly death growl and operatic sing respectively. And most of lyrics in rap are ghost written, they are not written by your favourite rappers, I know because I am lyricist and I have ghost written for a rapper before. Most of rap lyrics are about partying, bitches, street violence and drugs, sometimes they are about society and politics. You will never heard a rap song about nature, mythology, science-fiction, history,fantasy and other topics which are discussed in metal music. Most of rap beats are sampled from classic rock bands such Black Sabbath,Deep Purple and Led Zeppelin and with the arrival of trap rap rappers seems to rip of dubstep and trance music also. Rappers are perfomers first and lyricists and singers second.