The issues the OP has are with resolution and compression...not Contrast and Brightness.
Both of you guys are right on. I went through the same exact thing over a year and half ago and while I dialed-in some of my settings a bit "better", none of that had any significant bearing on the resolution, compression, and artifacts we were definitely seeing.
The OP's complaint has little- if anything- to do with those settings. Those settings you mention will do nothing to make the artifacts go away, increase sharpness or color information.
Those things can be done manually to at least get one within an acceptable range, which'd be necessary only if they'd been set way wrong.
While I wasn't a happy camper at the time (other than getting our HD locals back, which DirecTV unceremoniously took away from us), I knew that over time, my wife and I would eventually "forget" the PQ comparison and would come to "like" (or at least accept) the HD PQ from Dish without any more complaining ... and that's exactly what ended up happening.
I realize some folks simply do not accept that there is any discernible difference in HD PQ between the two, but we definitely saw it and spent a lot of time trying a number of things to trouble-shoot the potential issues or to outright cure the problem, but it turned out to be a case (for us) of "it is what it is". Truth is (again, for us), and I don't mind admitting it, the Dish HD PQ is not bad per se, we just found that DirecTV's was better when it came to resolution, compression, artifacts and associated issues. I am sure if we had not had DirecTV HD to begin with (the provider we made the switch from SD to HD service), then we would have been extremely impressed with the HD PQ from Dish and with no complaints.