Sounds like the problem with your dishwasher is more chemical than mechanical.
Numbers of complains like yours increased dramatically because since July 1, 2010 all dishwashing detergents are now phosphate free to comply with various state regulations. It might be cleaner for Environment but definitely not for dishes.
Phosphates were added to detergents to sequester minerals in water and thus improve wash performance. Detergents without phosphates tend to leave mineral deposits on glassware and other items, leading to poor wash performance.
So far in some detergents like Cascade Complete All in 1 ActionPacs phosphates have been replaced with enzymes. It works pretty good as a power booster, but there is one trick. DO NOT rinse dishes prior to load them into dishwasher. Enzymes would not work without grease!
The use of a rinse agent in your dishwasher may also help to minimize a repeat build up of film.
Also you’ll need to use a dishwasher cleaners on regular basis. There are a few of them on the market. I’m using for my dishwasher Dishwasher Magic which works very good.
Gene.