Tupac is the, if not, one of the realest and greatest rappers to come. He might have dealed drugs throughout his life, but so did many other great BANDS (i.e. The Eagles, Led Zeppelin, Piink Floyd, AC/DC, etc.).
2PAC was convicted of rape, and even though he didn't do it, he finally had some hardcore evidence he was a gangster. He didn't rap gangster rap because he rapped about realness. You could tell he was real when he was right about his death.
2PAC was also known to smoke marijuana and deal drugs as a child to make a profit. Some of his other means of profits would be by winning freestyle contests. Once, he won $200-$300 in a rap contest but spent it all on the rent.