In a perfect world...
...preseason games would not exist. The only reason they DO exist is greed, so the owners can charge regular-season prices for games that mean nothing while coaches settle their rosters for the upcoming season.
Instead of preseason games the teams should have controlled scrimmages against one another in training camp, not masquerade the events as real NFL "games." The scrimmages should occur on Saturday evenings or Sunday afternoons and tickets should be $25 apiece. Season ticket holders should be able to re-sell tickets for these scrimmages without penalty if they so desire.
Controlled scrimmages would involve teams within regional proximity of one another to minimize travel. For instance, the Patriots would scrimmage the Giants, Eagles, Redskins, etc. Controlled scrimmaging would help minimize injuries while giving teams a chance to hit someone else.
The coaches would meet beforehand to determine which specific drills/scrimmage situations are needed to test their new players and personnel groupings, respectively. For instance, if one team has an unsettled offensive line and the other team wants to figure out its defensive backfield, certain drills and game situations would be tailored for those purposes WITHOUT EXPOSING OTHER KEY PERSONNEL (starting quarterbacks, etc.) TO THE HAZARDS OF LIVE CONTACT.
The upside for controlled camp scrimmages vs. preseason games: fewer injuries/less wear-and-tear on players, a price break for season ticket holders and the opportunity for those without season tickets to affordably see the team in action.
The downside: less money in the owners' pockets.
My main concern is injuries in preseason games. Every year, some teams lose starters to injury in preseason games and it just isn't worth it. Of course, I'm speaking as a fan, and not an owner.