While I can understand your frustration regarding the time it takes to gear up to progress further through inferno, there is no item duping nor exploits "blighting" the game.
Most of the rumours of such going round are just that, rumours. The few that have been real have been stamped out by Blizzard very quickly and any problems arising from it resolved.
Lots of people seem to love making up rumours slating this game, which quickly become "internet fact".
Exploits. They exist. See above.