Wall protection.

Since MLB does not seem inclined to follow my recommendation and put pole vaulter pads along the walls, here's a no tech alternative to protect players from injuries due to crashing into the walls. Make the warning track off limits. A fly ball caught after a player has stepped onto the warning track is not an out but is in play. Yet another devilishly clever way to improve baseball. What's really amazing is that even simple stuff like this is beyond the grasp of baseball people, both fans and professionals.