What is your personnal opinion on the Iron Horde created by Garrosh Hellscream in AU Draenor which served as the main antagonist group of Warlords of Draenor ?
Of all the major antagonist factions the Iron Horde was clearly my least favorite with them being basically an AU and poorly well-written version of the Old Horde, with a catastrophic lack of characterization and depth for the Iron Horde leaders even if there was potential for them to get deeper and more complex writing especially for Ner'zhul and Kilrogg Deadeye; plus the fact that unlike the Scourge and the Burning Legion they didn't feel like a real threat to the Alliance and the Horde at all with their so-called apocalyptic invasion being comically easily thwarved by the adventurers and them having tried to invade without having conquered and secured Draenor before with the Draenei and Arakkoa and the Primals and Breakers still being well and healthy factions on AU Draenor.
There was also lots of wasted potential with them with their alliance with the Ogres of Highmaul being little exploited despite it showing some interesting promises with the potential of AU Orcs learning arcane and of the Iron Horde using the magic breakers as a way to counter MU Azeroth mages and other magic users, and also that many clans such as the Dragonmaw or Bonechewers weren't seen at all in WOD, and also their leaders being killed so quickly and easely with Kargath Bladefist and Orgrim Doomhammer being the most flagrant examples, even when they were supposed to live longer and have a greater role in the Alpha.
I think it would also have been more interesting to see some tensions and internal rivalries inside the Iron Horde from the start, with Blackhand being shown to be ambitious and ressentful of not being the warchief despite his clan being the strongest and industrial heart of the Iron Horde, or of other chieftains thinking that Ner'zhul (as the spiritual leader of the Orcs at the time) should have been the warchief, or being upset about dark shamanism (which wasn't used on Draenor until long after the elements had broken their ties with the Orcs due to the genocide of the Draenei).