I always felt the difference was that a 2K game felt more like a night game (like an "ESPN Wednesday Night Baseball") kind of vibe and The Show has more of that day game (sunny afternoon at the ballpark) vibe. It's that kind of buzz that goes through the crowd that seemed more amplified in 2K. I also think that's behind some people's "stale" comments when talking about The Show's presentation.
Personally, I think that what The Show captures, it captures better (and is more representative of the majority of a baseball season)...but, it would be nice to see more time spent on the excitement of baseball (since the nuance is already done so well) as the season progresses.
The enhanced playoff atmosphere helped with that greatly...we just need to translate that better to other prime time or key games in the regular season as well IMO. For me, this is where SOTS is most missed, as it supplemented for some of that with chants, clutch plays, etc.