The batters will get rewarded for having more power as well. Hitters will receive an additional minute of swings if they hit 2 home runs projected to land 420 feet during a single turn and if they hit a homer of at least 475 feet, they will get an additional 30 seconds.
If there are an head to head ties during the event, the two batters will compete in a 90-second swing off during which the clock must not stop and no bonus time will be given. The player that gets the most home runs during the 90-second span will advance to the next round.
If Yoenis Cespedes participates, he could be the 1st player ever to win the Home Run Derby in 3 consecutive years. He might then be able to with Giancarlo Stanton injuring his hand and being out for 4-6 weeks, missing the Home Run Derby and the All Star Game.
Here is a photo of all of the rules and how the bracket goes for the Home Run Derby:

The Home Run Derby will be played differently, with some people not liking it, and some people liking it.