Quote Originally Posted by paulwoods13 View Post
I don't know precisely when the rules changed, but it almost certainly coincided with an increase in players on the game roster. Coaches would have insisted they needed time to make substitutions to use those players.

IMO a 30-second (or better yet 25-second) play clock would prevent some situation substitutions, the vast majority of which are made by defences shuttling in rested pass rushers. I don't think it would have a huge impact on either side's ability to read and react to a play as it unfolds. But it would mean more snaps, which means more chances for something exciting to happen.
Good point about substitutions. I fully support a faster play clock. It also means fans spend less time sitting on their hands waiting for the next play to get off, which I think is an important consideration. Attendance and viewership really started to drop about ten years ago when video review and challenges were brought in (along with revised PI rules), leading to far more down time during games.