Richard at Philosophy, et cetera has an essay on whether the Gracchi brothers were genuine reformers or just political opportunists.
For those who, like me, enjoy studying the Roman Republic it is a good read.
Personally I disagree with Richard that they were reformers. I think they were the first in a long line of populists who destroyed the very stable government that the republic was. The Gracchi are probably second most culpable after Gaius Marius.