When you think about it, the recharge time and regen strength (+ AOE size) just feels completely out of whack. All it does is regen and nothing else. It's not a heal, with a gentle reminder there is no burst heal plus heal can wake people from sleep. Regen can't. Yes it is a larger area than most PBAOE heals, 25 vs 40 ft, but those are 8 second cooldowns compared to a whopping 200 seconds. Once every 200 seconds you can place an immovable 150+ regen buff?
I know this is breaking the cottage rule but I almost wish Time Bomb could become a device that acted like a Banished Pantheon/Circle of Thorns endurance crystal, that pulsed +end or something, then swap its place with Trip Mine in the list, making Trip Mine the tier 9.