It's not a matter of getting better at tagging people, if you tag someone on the arm they can swim into the other arm, if you take someone on the body the arm might get there first, there's always a chance if you're tagging someone on top of the base that you're going to get beat no matter where you want to tag them.
What you see as blocking the plate I see as simply going to meet the runner with the tag, which I think are two different ideas. I don't see it as a football scrimmage, as a defender you shouldn't be trying to hit the guy and as a runner you shouldn't be trying to hit the defender. The defender should be trying to apply a tag and the offensive player should be trying to avoid it. If the path is cut off because you got beat by the ball then your chances of avoiding the tag are near zero, as they should be.
What happened with Bo was a freak occurrence, he started sliding as the catcher got the ball moving towards him, leading with the glove, and it ended up in a collision. s*** happens, but you don't go and make the rules silly because s*** happens.