I would not mess at all with the NFL pre-season and regular season schedule. 16 regular season games already inflicts more than enough physical damage on the players, 2 additional meaningful games seems like a poor decision for everyone's health.
Oh, but the fact that teams force fans to pay for stupid pre-season games bothers you?
Please believe a lot of the cost of the forced payment for those shitty games is already reflected in the pricing of the whole package. If you just made season tickets for the regular season and sold pre-season games as single game packages the price of regular season tickets would go up quite a bit. I would be one surprised dude if the cost of season tickets did not increase if the NFL went to a 2-18 format instead of a 4-16 format.
Look, the NFL is hugely popular, so the league will find ways to extract money from its fans because the fans are like a giant mass of twitching meth addicts. So let's not mess with the health of the players which provide the excellent product we all enjoy by making them beat the hell out of each other two more times a year.