Us old timers can remember the day when there were SIX preseason games. (That you had to still pay full price for that didn't count!)
I think it would probably be a good move.
What I would do is start the preseason with a controlled scrimmage, as opposed to a first game. (televise it locally)
Let the last place finishers play in the HOF game, and the international crap. (They need the extra work anyways)
Then play one full preseason game.
Then play 18 rsg's.
I used to like opening at home on Labor Day weekend.
Go to a game....cook out...tailgate...party...stay until dark.
Then you have all of Monday to sleep in and unload the car.