I just watched the not very recent video of Archimonde mythic first kill and i was thinking, very good boss, the fight is dynamic, he talks very cool but the predictability ruins it for me, i know he will loose and get killed, no matter what he says, like all the bosses before him which makes it in a way boring. It's definitely harder to think of a way how to make us the players loose by a boss since deleting our characters won't be very good for blizzard economy, but it's not impossible. For example they could have made it: Fighting the boss until the end of phase two and in phase tree boss gets serious and we are forced to escape from him. And if i was a paid blizzard employee thinking all day about raids i'm sure i will come up with many more unexpected situations other than killing the boss.
So what do you think, have you noticed this monotony in raids expansion after expansion and does it bothers you ?