2 PAC vs TODAYS RAPPERS SONGS LYRICAL SKILL?

Today's rappers are mostly bad however there are some decent ones like Papoose, Cassidy Lloyd Banks and at times Lil Wayne.I'm also a mark for Ludacris.What makes them good is their lyrical ability and for some their songs.However,2 Pac had better songs and for the most part better albums than most rappers today.A big argument I always have with people is WHY DO THEY BASE RAPPERS SOULY ON SIMILES AND METAPHORS?If we are having that argument than you might as well say every rapper today is better than 2 pac which I and most people I know wouldn't agree with.I have heard a lot of great lyricists in my day but are most of them selling Diamond like Pac did?Nah I don't think so.So the question is who made rap souly about similes and metaphors being the basis we judge a rappers skill on?Imo you can be nice on the mic but have no catchy songs what so ever.Don't get me wrong pac did have his moments here and there but for the most part he wasn't a punchline rapper and his music was still awesome.What is your take on this argument?