House of Wolves was middling, as far as expansions go it was pretty forgettable.
2/5
Dark Below had an interesting concept, and it help set up the pieces for the best Destiny expansions story and many more stories to come if the story is going in the direction I think it is. But it was short, and the Raid wasn't my favorite.
3.5/5
Rise of Iron, should be called Age of Triumph, because that's when the real expansion came out for me. It was good, but the only reason I could see anyone thinking it was great was because it made everything relevant again and even then that came in a second update. The raid was okay, the plot felt wasted.
3/5
I can't speak on Warmind, I haven't played it yet.