This was also brought up already, doesn't seem fair that you still get credit for someone else executing a guy.
As long as executions count instead of downs it isn't really fair that you don't get the credit for someone taking the kill you worked for. It goes both ways
last I checked this is a team game, and I don't know why people are even leaving their downs crawling around for that long so much anyway, I personally can execute most of my downs fairly easy anyway so I hardly run into this problem. And If I see an enemy crawl away and my teammate isn't finishing the job you can bet that I will so we don't risk him getting revived.