Maybe revising the current "Substitutions" menu (does anyone really use all the options? I don't think I've ever used anything besides Strictly Follow DC) and giving users a legit "rotational subs" options would be ideal.
If you value winning more than training for a particular game, Let Coach Decide is your best option. If "Depth Chart til 4th" actually worked, it would be a viable compromise between winning and training, but it doesn't, and hasn't for a long freaking time, so that's irrelevant.