I never talked about blocking preimeter shots either. Let me try and clear this up for you.
Good shot blocking big men allow guards to play their men tighter, but this likely has little to do with the game engine.
When the big mewn are good shot blockers then outside players can stay within arms length of hteir men due to the fact that if their man beats them they have good shot blocking behind them to help. It is more or less common knowledge that good bigs help perimeter defense in this way. However, I agree that this might be difficult for a game engine to account for.
However even if a guard is a good shot blocker himself he can tighten up on his man because he can better recover from mistakes if he gets beat. Again though, I'd be very surprised if this was accounted for in the game engine.
This part also has zero to do with blocking jumpshots. Simply put, if a guard is good at blocking shots himself it can have similar effect to solid bigs. If you are a guard and you get beat by you man what are your options? You pretty much have to try and block the shot. If you suck at recovering to block (or bother) shots then you have to lay off your man on the perimeter so he can't get by you. This meakes it easier for him to get open jumpshots from the perimeter. If you are good at blocking shots you are less worried about what happens when you get beat and play your man tight. This makes it nearly impossible to get off perimeter jumpers. Thus
making it much more difficult to score from outside.Again though, not likely to be part of the game engine, even if it should be.