Solution 3: Surprise
More encounters need more surprises more often. The best recent example of an encounter that utilized good surprises was Twin Valkyrs, though this can be pushed much further without making raiding unenjoyable. Another good example of Surprise in raiding are the Anubisaths in the caverns between Princess Huhuran and Twin Emperors, which would randomly use two ultimate abilities that necessitated entirely different strategies be coordinated on the fly.
A poor example of Surprise came in the hallways immediately after Twin Emperors with the random groups of trash mobs. Pulling too many of the mind-controlling mobs made pulls extremely frustrating. Surprises should not offer significant differences in difficulty, only significantly different requirements in approach.