not a good idea. Although its only for the weekend, all the drops people are getting would severely lower prices for everything for months to come...so it would be like the great GW depression
Mithran also makes a good point. You won't see so much as a single farming group; everyone will just hench up and go. There's enough of a split anyway thanks to the overuse of heroes without a system that directly rewards you for taking bots over human players.