It has, mainly because of its low base power STAB moves, somewhat bad typing, and 3 moveslot syndrome because it really, really wants Protect. Adamant Hammer Arm can't reliably OHKO Kangaskhan, Clefairy can survive Iron Head without Intimidate (example given just to give an idea of how it barely misses out on a lot of OHKOs), it has Aegislash/Heatran/Landorus-T problems, and as a Steel-type for rain+steel teams, it's outclassed by Aegislash.
Hydreigon not being as good right now is also a factor. Hydra+Meta seems like a cool defensive combo until you realize neither wants to be taking too many hits and isn't flexible enough because Metagross really wants to Protect turn 1 and Hydreigon likes to be Choiced. It's weird how something with such high defenses could be considered not bulky.
e: why is this in C&C lol...