The fact that it's "impossible" based off some ilevels makes me think Blizzard's current design is pretty flawed. Excellent play and decent gear should be a boss, normal or heroic. Ever since the introduction of heroic modes (Uld was so amazing we didn't consider it) the game has gone down hill. I liked having to kill bosses like Illidan once a week on a single character. We killed it, great, we get good loot. Back then, it was so much simpler.
I'd love for them to merge heroic/normal together and make the difficulty in-between, causals still have LFR/flex and raiders get one single unified mode.