I believe Spring Training is hard-coded to start in early March. But what if your league is in Australia? A true major league there would play, what, October to March/April? They need spring training starting in August/September.
As for me, I'm contemplating a short major league season in a country with a start date of May 1. Early March spring training would be far too early. I'd need an April 1 start.
So how about adding an option to allow the player to choose either going with an early March default start, or changing the start date to a date of his choosing? Ninety percent of games will ignore this, but the other 10% will be grateful for the option. That's thousands of gamers right there.
EDIT: I see upon further review that the game can automatically adjust spring training start based on your season start date when creating the game. If your league evolves with changing start dates, though, this won't help you. But I guess most leagues won't. So, never mind.