So I only recently found out about 'Reveal' which is on the P2W vendor, entirely free of course (other than a bit of inf). It's fantastic, but it still doesn't really fix one of my biggest pet peeves when it comes to missions.
There have been so many times that I've been in a mission with a 'rescue X npc' or 'defeat all' targets. Now, when there's just one or two enemies on the map left, an arrow will pop up on the map showing where they are. Thing is... on a big or complicated map, especially one with a lot of veritcal space, I've found myself spending so much time trying to find what I'm looking for that I give up in disgust and either complete the mission automatically or abandon the mission entirely. At least with 'glowy' collect or place targets have a noise that tells you they're there.
That 'last enemy' showing up on the map tells me that it's possible to reveal an NPC or target on the map.
My suggestion is this : a P2W power that you can use that reveals ALL NPCs on a mission map. Like the existing Reveal power, you wouldn't have to use it, but it's still available. Being frustrated by some pack of NPCs being up in a corner of a large room and you just can't find them is something that detracts from the experience of the game.