I suspect I'm unusual in this opinion, but I think
catcher is just as important as SS. It can take some digging through extended stats to appreciate the kind of impact good and bad catchers can have on the game, but it's real.
Consider: aside from the pitcher, what defensive player is immediately involved in every single at bat? Catcher. Every play. (Every pitch— although developers have been explicit that the engine does not simulate individual pitches, just at bats.)
Here's an extreme example:
Hardball Dynasty – Fantasy Baseball Sim Games - Player Profile: Dennys Franco
Put this guy on the field, and the whole game changes. It's beautiful. Only catchers can have that kind of impact.
Right... putting my soap box away.