OK....gameplanning stuff....
- The "amount of work" needed to implement the game-planning for your CPU opponent each week is minimal. It takes less than 2 minutes. You don't need to control every team, just the one(s) you are playing that week.
- Regarding your own gameplanning; the XP gained during drills is pretty insignificant in the grand scheme of things (assuming you have always been simming your drills to a bronze level - which you always should do to be "on par" with the CPU....who will always max-out at Bronze).
- If you choose your own drills, yes, you can get little boosts for certain play types (potentially allowing you to exploit the CPU more). But bear in mind, that the CPU seems to choose their own drills pretty randomly, though I haven't studied it in detail.
- For coach schemes: My current recommendation is to enact the gameplanning approach and either a) leave them alone completely or b) just minimize/eliminate the teams running a vertical scheme.
Look...I've got to be honest. The improvement in the CPU play-calling variety from implementing the gameplan tweaks is SO well worth any potential downside. It "levels" the playing field versus the CPU and it adds a lot more complexity during the games.