Madden players tire out at different paces
I like that concept, because it's an idea in the real world of athletics that is often ignored. athletes tire out at various rates, they're both resilient and vulnerable to different items, some athletes can consume one gallon of gatorade and not be a problem, while others might only require one or two cups before they're finished.
Similar to things like exercising, certain players might build muscle more quickly than others, and some players might gain weight faster. In my opinion, that a player's path to success should be taken into consideration more than twofold. If you have a child who was born in Florida or who attended university somewhere located in southern Florida they'll likely be less successful in a location such as New England, or Cleveland, Pittsburgh, New York, Philly, Green Bay or a similar location since they're not experienced with snow.
I'd even suggest that it would add a new dimension to drafting. If you're working in a franchise model using Pittsburgh or Denver and you don't want to be looking for someone who has an insensitivity to cold or high altitude. If you go back to the idea you mentioned that you're seeking someone who can be a gunner in your punt unit and you don't want choose someone who tires out in a matter of minutes. This is a great idea that you've brought up that I've never thought about. thought to.
Strangely enough, it's included in NHL games that are also developed by EA and has an integral gameplay mechanic ever since NHL 07 was released on Xbox 360 and PS3. If you play any Gen 7 8, or nine NHL game, and if you don't change the lines for long enough, it will do several things:
The players move more slowly
The handling of pucks is more clunky and less flexible
The effectiveness of hitting is lower.
It is harder to win fights
The radius of turning is more
Injuries are more likely
The weaker shots and passes are far less precise and much less precise.
Also, the NHL games aren't amazing, but the idea of rearranging your line combinations efficiently was widened to a point that affects the way you play it's a simple thing that's vital to the way these games are played, and is something that Madden does not have. There's no reason to take your starter off, as there's no reason to keep them in. If a player is injured in Madden the chances are that it's not anything that's within the player's control and more of a case of bad luck.