Don't get me wrong, I am not saying that preseason games are a waste of time.
Preseason games are a great way to separate the players in your training camp that you want to keep and the players that you want to release. It is great to view other team's backup players, and check potential threats if a starter is injured in the regular season.
What I am trying to say is—don't predict a team's season by their preseason games. As I said earlier, most CFL teams are playing their backups, trying to decide how the team roster will be filled, and the placing of players on the depth chart. Starters are starting games, but not usually finishing them.
For example, in the Winnipeg Blue Bombers' first preseason game against the Hamilton Tigercats, seven quarterbacks in total played during the course of the game—three for the Bombers and four for the Tigercats. Teams are checking out all players to separate the best from the rest.
Therefore, don't trust the scores of the preseason. For example, the Tigercats beat the Bombers 12-10. However, it is being predicted that Bombers are Grey Cup favorites, and Tigercats are looking to have a last place finish again, even though they acquired QB Casey Printers.
So, you make the final decision about preseason games. If your team is scouting backup players to fill a position or deciding who should start and who should be a backup, then don't trust the preseason scores to predict your teams success this year.
However, if your team keeps your starters out all game and loses, I would be worried, because all the other teams are using backups. If your starters can't beat the backups, how can they beat the starters?
Sources: bleacherreport.com (CFL Preseason: Hamilton 12, Winnipeg 10 by Matt Eichel)