4th Substitution Only Timeout Instead of 10 Seconds Before Snap Rule

I came across this suggestion on SI.com for a better rule change instead of requiring the offense to wait to snap the ball.

Given how much the rhythm of games has changed of late, it seems reasonable to suggest that teams should be given a fourth [timeout]. People might complain that games are already too long -- with increased stoppages in play and longer TV timeouts -- but that seems a fairly benign byproduct compared to the significant strategic and game-management consequences that hurry-up, no-huddle coaches are bracing for if the current proposal comes to pass.

Furthermore, the rules could stipulate that this extra timeout be different from the other three in that it would be used specifically for substitution purposes. It'd be a 30-second timeout that a coach could elect to use if he sees a player in distress who either can't or won't get off the field. If the coach does use this emergency timeout, the player in question must come out of the game for the rest of that series. This would address the purported motive behind the rule change, take away any excuse for why a coach can't address player safety and minimize a coach's ability to horde this extra timeout for schematic purposes.

Thoughts?