I don't think the gambit part appears particularly difficult myself. To be honest, it's about the annoyance of it. I did all the gambit related quests before they were nerfed, so if I got those done, I can definitely get this 1 kill done. The annoyance is that if you have a team of guardians, and everyone is looking for the same thing (kill an invader before they kill anyone on the team), you have are forced to keep playing a game mode, you may not want to play, in hopes that you are in the right spot at the right time, when someone invades, hope you have ammo for a quick kill, hope you get it before your teammates get it, hope you get it before the invader kills anyone (or even damages them so I hear as its bugged somehow). That's something that would happen naturally, but the community doesn't want that, because it could take 1 game, or it could take 20 with crap luck.