S9 was very melee cleave-populated, with I think DKs farming casters left right and center. Anyone remembers this? :]
S10 was actually pretty good and I honestly can't remember anything being too OP or UP in it.
Sure, I had lots of fun while playing MLS/FLS early on, but then one more thing happened that made Cata absolute garbage unless you already had a bunch of people to play with. Smaller realms literally died during s9/s10, especially after the mmr fiasco. Often you simply couldn't make any viable comps anymore, because you had maybe 3-4 players that were 2.2+ capable, but you were fucked if they happened to play the wrong classes/specs.