I had seen posts by another 5020 owner who reported similar difficulty, in that he received several projectors, none giving satisfactory performance. I didn't want to believe that Epson - who I admire - could have bad enough quality control to send two bad projectors to the same customer, but I seriously think that is what is happening to you. You posted earlier that they offered to send out someone to your home. It is probably time for that, but I still think the ghosting you report can only come from a defective 5020 or defective glasses. Without any doubt, you are describing something vastly inferior to the picture the 5020 delivers to most customers. You are not just overly sensitive or anything like that.
I have had four 3D displays in my home, including one DLP, one passive LCD, and the Epson 3010 (2 of those). I have used them all to view many 3D movies and many 3D videos I produced myself. I don't claim to be any super expert, but I know what ghosting looks like, and I know what the Epson 3D projectors are capable of. Yours should be doing far better than what you see.
Maybe if you were setting extreme disparity values into your video player, you might be able to create objectionable ghosting, but that would require you to be telling your player that you were viewing on a 27 inch display when you were really using your 80 inch. And, your player would have to have a place to put in your display size (The PS3 does). As you noted in your original post, that is not your problem. The only other possibility I know is a defective 5020 or defective glasses. Sorry. Yo probably are just getting unusually bad luck.
Don't give up. A right 5020 is a thing of beauty in every way.