At least IMHO....
First (optional suggestion but works especially well for closer idea to follow): Change Pitching Camera to Minnesota's as it is the farthest away from pitcher/catcher and bring it back from there as far as is possible. Then, shift (to taste) to the right or left and up a bit---slightly over field umpire's head....Hard to get used to at 1st but then seems more like the actual distance one would see when really on the mound. All the tv cameras except Minnesota's flatten out the distance. This greater apparent distance of the Twins' altered camera makes it more difficult to pitch in precisely in MLB The Show. For franchise I use this setup in two variations: Shifted to one side of the pitcher for home games and shifted to the other side of pitcher for away games. Again this is optional but, again, to me, makes pitching much more challenging.
Now to the main part referenced in title of thread,
Basically, just this, use 2 different mechanic types in a game:
-One for Starting/Mid/Setup pitchers---I use CLASSIC pitching on Legend here with slider adjusts particulary on accuracy/consistency to make it harder still and,
-2nd one for closing pitcher--I change to PURE ANALOG* here (switched as soon as my team goes into final at bat and closer is warming in bullpen) and adjust pitching difficulty down to Hall Of Fame. If the game is on the line the newness of the mechanic (and your-most likely-already built in nerves) makes for a much more riveting time.
*If you choose to give this a go and try the PURE ANALOG route I would suggest not using the meter at all but go by leg kick of pitcher for delivery. To aid in this (when editing camera above) change the meter to the triangle type; reduce it to its smallest possible size and move below and to the left of pitcher so as to be mostly out of your view when delivering pitches.
Try it you may dig (or not).
Throwing it out in hopes it may add some furtherance of fun and variety to your gameplay experience during a long season(s) the way it has for me.