NFL has had an eye solely on getting everything perfect when it comes to rules. But they have not considered the impact to the quality of the product. I think that element has hurt their numbers. There's a lot of people who hate games hanging on the officials that's for sure.
What they should be looking at is efficiency and limiting what the Refs have to look for. The easier the rule set the more likely they are to get the calls right IMO.
And re: replay I'm fine with it but it has to be fast. Way faster than it is now. I cannot stand that it's easy as a fan to see a couple quick replays and have a good feel for what the call should be, then you have to sit and wait through commercials and all the BS to get the result.