At the start it definitely wasn't. The pandas were the first grievance voiced followed by how the daily quests functioned at max level then reforging came under fire for how much min-maxing it encouraged and people felt like they were visiting a tool and simming to see what had to be done with every new piece of gear that dropped and that it wasn't very interesting (they never really addressed the root of the problem with that sort of thinking and just removed it in the end) lastly topped with issues with the pvp gear levels and I recall something about raid loot. Later on there were some gripes about the legendary quest but after the patches stuff was generally positively received, Isle of Thunder and the Throne raid, Timeless Isle and SoO.
Of course at the time people didn't know what or how the next expansion would turn out and didn't realise how much better it was in retrospect.