yeah, MLB and MLBPA rules and contractual agreements certainly put limitations on what the dev team may be allowed to do. But in addition there are both advantages and disadvantages of The Show being a 1st party Sony game/Playstation exclusive also.
Good that they don't have to worry about as many platforms - and now only have to focus on PS4 version since PS3 and Vita versions are retired. Which makes me hopeful this year's game will be the biggest step forward on this gen.
But not as good that their revenue stream is more limited. Imagine if this was a 3rd party title that could also be sold on Xbox, maybe some Nintendo platform and PC/Steam? Instead of 900k copies or whatever they sell per year now as a Playstation exclusive, what kind of budget and resources would they have if they sold more like 2 million units across all platforms?
That being said, The Show is the only game I buy every year, and I am thoroughly satisfied with my purchase every... single... time. Year after year, the quality of this game is top notch. And considering the dev team is less than half the size of the other Big 2 sports titles (certain basketball and football titles), it is quite an accomplishment.