I donno....I don't really like the fact that he does this.
I have different views about it personally. Yeah, many rappers do use lines from popular songs that everybody's heard....but not only does Jay do it TOO much, but he takes lines from songs that only some people have heard. I know I'm not the only young buck who didn't know that he stole the entire "99 Problems" line from KRS One. People our age are like "man Jay is a genius, that line alone is proof" but he stole it, and the same goes for many of his other lines that people too young to know that he's stole lines would know. Like how he bit a grip of Slick Rick lines on "The Ruler's back" that's not "liftin up his brother" or just givin props to me, that is doin too much if you ask me. He definitely uses TOO many of Big's lines.
My main problem would just be for the future generations. I definitely feel he's one of the top 5 rappers out, and probably top 10 ever, and when the future generations will hear about him, they will seek to hear his music, and they will have no idea that he "borrowed" 100s of lines from other rappers and songs, and when they do find out, they might not see it like we do. Some may say ignorant things like "damn, Snoop and Biggie used to always copy Jay-Z!" and some may be like "he can't be that good, he used everybody else's lines."