I agree with the previous posts that putting a limit on the number of transactions is the best way to keep this from happening. If you put a cap in place, you won't need to change your stat categories.
We had a limit last year of 44, but to be honest that was pretty tight - I had a hard time staying under it.
But even with a cap, you're inevitably going to have this problem: Owners who make the playoffs will pick up and drop pitchers on a daily basis in an effort to try and win a playoff series. At that point it will come down to Ks and Ws. I've been guilty of doing this myself, and it works sometimes, but not always. Many times the owner who has hoarded the most transactions and yet made the playoffs will be in a good position to win it all.
Hope this helps,