I think there are rappers today surpass tupac on many levels. There are a great many rappers today that can put words together better than tupac, its just the words and meaning they choose that make them less important and entertaining.
Tupac rapped about many things, problems in the world, politics, religoun, and his beliefs and expierences. No other rapper touched the diversity he did and this is because no other rapper can. He put everything he had in his music, not what people wanted to hear, and this is why many people can relate to his lyrics.
I do beleive there are better rappers at freestyle. Emenim and canibus can freestyle on a level that i believe that tupac never achieved, however theire lyrics never really break free from there repetitive trend. Rappers like NAS and DMX are in my opinion the best rappers of the day. They have that great substance in there lyrics tupac had. The thing is however these rappers were all inspired in some way by tupac.