Now, before you point out the proximity of this post to Wang's injury from Sunday, I want to say that I'm all for pitchers having to hit and the strategy that comes along with their spot in the lineup. But even so, the National League needs to add a DH.
However, I'd call it the Designated Fielder and apply it to both leagues. I may be running with an idea that I read a few years ago, but here is what I propose. Each team would select a designated hitter to hit for any fielder on their team EXCEPT for the pitcher. This would allow aging stars and unathletic sluggers to play until they are 45 while adding an exceptional defensive player who will make incredible plays in the field. These defensive specialists rarely crack Major League rosters since they can barely hit above their weight.
This plan would force pitchers to face retaliation for their chin music rather than the team's superstar and the combination of improved defense along with the pitcher batting would speed games along. All of the strategy involved with double switches would still be in effect and offenses would likely produce at a rate greater than the current National League average since a weak hitter would be replaced by an aging star. And to make sure the union is on board, I would raise the roster size to 26 players adding 30 new members to the MLBPA.
It's a plan that works for everyone. Fans get to see better baseball with lots of strategy, 30 new jobs get created, and pitchers will be more accustomed to batting or running the bases that injuries like Wang's will not occur as often.