So, GP says "Vote for people who aren't interested in taking bribes" and you say "eliminate the donor class" -- those seem like pretty distinct policy recommendations. How are they related?
The only way to run a modern political campaign is with lots of cash, so the cash must be procured somehow. Your two options are to level the playing field with public funding of campaigns (unlikely to happen in the wake of Citizen's United) or for a candidate to raise small dollar donations. The Sanders campaign proved that the latter is possible.