How would the Oregon and Ks State games have been less important with a 4-team playoff? Would those teams just have mailed in the game, assuming they'd keep the top 4 ranking even if they'd lost? That would have been a mistake, because they both fell out of the top 4 with their losses to Stanford and Baylor. It's likely that in a playoff system, at least one of them, if not both, would be left out because of their 1-loss record coupled with other perceived deficiencies.
With the playoff, we would have been treating many other team's games as championship play-ins, ie the games of UGA, Fla, Oklahoma, LSU, FSU, SC, etc, even though they'd already had a loss. Under the current system, these teams had been written off long ago. The new system calls for more than only the teams with undefeated records to have games that can make or break their chance to finish in the top 4 and compete for a title. Now, 2-loss teams will still be in the hunt, perhaps hoping that the 1-loss team which would otherwise take the 4th seed will lose so that they can jump ahead of them and into the playoff.
The NFL comparison is flawed because there are more games during the season and more teams in the playoffs. The problem occasionally emerges where a team has a bye locked in and can mail in the last game or two (although this is pretty uncommon). Regardless, there are usually several critical games at the end of the NFL regular season, with teams at least fighting for home-field advantage if not for a playoff spot itself. Also, teams that are not in the playoff picture commonly shut down their A-game to protect their rosters from injury, preserving their personnel for the next season, which can make for boring games. College teams don't do this as most of the players are getting their only shot.
Regarding baseball, it is true that the wild card expansion is bad for the better teams. But it definitely makes more games relevant. Not only is there the division race, there is also the wild card race.
Given that in college there are still so few playoff spots under the new system, and so few games during the regular season, I sincerely doubt there will be a disregard for any of the games by any of the collegiate teams. It will be very tricky to get in, with nothing for certain for any team that loses.
Would anyone here have felt ok if Yeldon didn't score the game-winning touchdown against LSU, just because there were 4 playoff spots? Would the team have just thought, "no biggie, we'll get into the playoff anyway. . . we'll just mosey on past Texas A&M"? Obviously, with the A&M loss, Alabama is still in it this year. But a lot of that has to do with recently-earned favor due to winning titles. Most teams, like Oregon and Ks State, don't have that luxury, and Alabama can't assume it always will.
The nail-biters won't decrease in number because there are two more spots. I think the opposite will happen. Long story.