Reducing playing time, for the pure and sole sake of reducing playing time, without any clear or relevant purpose or objective that offers a specific benefit, seems totally unnecessary and foolish.
The purpose is to adapt the rules to keep up with the evolution of the game. When the current rules were put in place there was a substantially higher percentage of run plays, practically zero fast paced offenses outside of hurry up situations, and less scoring. A much higher percentage of plays back then ended with the clock still running.
Now that the game has evolved we have a significantly higher percentage of pass plays (and incompletions), more up tempo offenses, more first downs, and more scoring in general. Those things have led to longer duration games and, more importantly, more plays per game. As most have seen via hudl or other sources, the number of plays per game nowadays rivals or even exceeds the number of plays that college and NFL teams typically run. In my opinion, high school (and younger) kids should not be playing games that consist of more plays than college and NFL games.
The point wouldn't be to make a change just for the sake of change. The point would be to adapt the timing rules that were fine for the gameplay styles of the past when they were implemented, but are now leading to game lengths and play counts that are higher than they should be.