+1, current system just seems like lazy coding. With how strong the rift mobs are, did they really intend for an unarmed noob with starter leather who gets a swing off to get the same points as someone who dealt 100% of the damage to a mob? Those doing the work should be rewarded more, if I were starting today, it would worry me more if the current system was their actual intended philosophy. Working towards something is a big part of this game IMO.
Granted, actual abuse of this system is probably minimal, personally I'm not bothered by those who do it.
If they want to keep the rewards system as is, so as to not disenfranchise "new players", fine, but at the least, make a more meaningful leaderboard with damage dealt, healed, taken, etc, maybe separated by waves. Other games have this. Could you imagine a popular game like DoTA or WoW where at the end of a pvp match, the statistics board only showed who hit the most people one time?
Bottomline, when you go to a rift, you should be spending time to help complete the rift. In whatever way you can/want healing, fighting, supporting, etc, because that's what's fun. Going to a rift and having to worry about running around and how many mobs you can tag is silly.