This might be kinda tangential, but I was trying out the newly-released Firefight mode in Halo 5 and the bosses in that mode are "hard," only in the sense that they apparently have astronomical HP. Otherwise they just stand there and you're wailing on them for 10 minutes trying to get their lifebar to go down. It's so disappointing and lazy. I'd say Destiny has similar types of bosses that are just bullet-sponges, although some of them do have creative visual and audio design. And I'm going to assume that the other MMO-lite du jour, The Division, has pretty much the same thing, although I've only played the demo. I think it's just cheap game design. How can we make this boss battle hard? Give them some outrageous amount of HP. These Western studios with their sense of superiority should take a step back and look at the boss battles of Japanese games, that even in the 8-bit era were already featuring bosses that go through two, three or more transformations in the course of a battle, each time having new patterns of attacks and weaknesses to learn. I guess maybe the Souls series carries on this tradition? I haven't played them.