Yeah, this is the only thing I hate about The Show (outside of the bugs). Why did they change it to random? They had fatigue in DD in '13. They have it in Franchise mode. I understand people didn't like playing against the same pitchers all the time, but they play against the same batters and relievers. Why make SP selection random? Why not also randomize batting order or who my closer is - makes as much sense. Use fatigue to limit pitcher selection (if this is really even needed to make the mode work) and apply performance penalties (when using someone not at their peak or too long in game) similar to using a player out of position.
DD is all about choosing the players you want on your team, so let people play whoever they want. I don't care if someone uses they same SP all the time. It's their team, play whoever you want. It really doesn't affect my enjoyment of the game at all. Not being able to choose my team does though. Also, the more I see a pitcher, the more I get used to hitting off him.
I'm sure the SP selection is in fact random, but if I save up enough stubs to buy an ace I want to use, I don't want to have to wait several games before I can finally pitch with him. It really ruins the experience. I got Greinke in a pack and was excited to use him, but had to wait about 8-10 games before it happened.