Al: One-platoon football is dead & it ain't coming back. Allowing for defensive matchups would maintain the balance between offense and defense that NFHS values so dearly.
I'm not looking for "one-platoon" football, any more that I'm looking for unnecessary rule adjustments to accommodate Coaches who refuse to prepare for
INEVITABLE REPETITIONS, common to the game.
Of course, most everything is local, and no two football games have
EVER been exactly alike, but deciding whether to kick, after 3rd down, is a reasonably consistent decision Coaches have to make during, at least a majority, of Interscholastic Football games, and a majority of Coaches are most often prepared to do so, on a regular basis WITHOUT calling for a "team meeting" to alert (usually) the same substitutes to repeat their standard assignment.
The value of pre-planning and preparation extends to both sides of the ball. Specific actions, usually call for specific reactions.
Both the Offense and Defense
ALREADY have exactly the same opportunities to plan, and be prepared for, multiple opportunities/challenges that may be determined by previous game action.
Some (actually, quite a few) Coaches have their selected "Special Teams" substitutes standing by, on alert, prepared (if not anxious) to enter the game upon receipt of brief, additional and specific instruction.