You've really thought a lot about this, I definitely agree with on a lot of this. One thing I would add to the list though is Young Ahamkara's Spine. It's buff is barely worth of an Exotic piece of gear. It it next to useless in PvP and there are better Exotic Perks to have rather than that one. Perhaps along with a longer timer on the grenade the lasers on the tripmine could be invisible? Or if that's too powerful perhaps the grenade could be immune to damage? So the opposing team would ever have to go around wherever the tripmine was placed or set off the grenade and get away before damage can be taken. Either way it needs a serious buff, it's not worthy of being called an Exotic and it is barely ever used.