Iron Man's biggest villain in the comics was a horrific racist caricature of China and Chinese people, I'm extremely happy they were not faithful to the 'true' Mandarin. Unless you're adamant on insisting All Hail The King is some sort of panicked retcon, all evidence of filming schedules to the contrary, it's evident from the start that they're still keeping the actual MCU Mandarin in reserve. I'll allow it was a wasted opportunity, but not that what we got was somehow a bad character.
Extremis...here's the list of abilities granted by the original Extremis serum, according to Marvel Wiki:
The original Extremis serum gives its user:
Superhuman Strength: An Extremis subject's strength can be increased to superhuman levels, providing the user enough strength to toss cars and people with relative ease, break someone's skull with a single punch, counter Iron Man's superhuman physical blows, break Iron Man's bones with ease through the suit, rip the highly durable suit apart without effort, and even use the "blade" of a bulldozer as a blunt force object.
Superhuman Speed: An Extremis subject can move and run at incredible speeds up to 300mph,, although it is unknown if this is the top speed an Extremis subject can move at.
Superhuman Stamina: The virus grants its user almost unlimited stamina, with no need to eat, drink or breathe air.
Superhuman Durability: Extremis-enhanced beings have greater resistance to physical injury than an ordinary human. They are able to withstand bullet impacts and direct fire of Repulsor Blasts without feeling pain, at a potency higher than which a Repulsor Blast needs to have to cut through metal, only suffering minor wounds. Iron Man's uni-beam only caused Mallen great discomfort without injury.
Fire-Breathing: At the user's discretion, his/her lungs fill with fire plasma which he/she can exhale through his/her mouth. Mallen torched a lobby full of people through this method.
Claw-like pincers: An Extremis subject can unsheathe stings from his/her fingertips. They are very durable, and in conjunction with super-strength, they can be used by the Extremis subject to claw through a converter box.
Electrical discharge: Extremis-enhanced beings are able to discharge extremely powerful electrical currents through his/her hands which seemed to emanate from his chest through his arms.
Healing Factor: Extremis-enhaced beings can also heal wounds at a incredible speed, in a matter of hours.
The only things on that list that weren't in the movie are the magic lobster claws and the electric bolts, and they ramped up the healing factor. Not a huge loss, IMO.
AIM - isn't it originally run in the comics by Modok, the floating head with little stubby limbs in a flying armored bubble? I have no idea how you could make a non-ridiculous Modok in the semi-real-world MCU that still bore any resemblance to its source material, and while I won't argue that Killian's scenes were very poorly scripted and narmy, his narrative role was solid.
Also, you're successfully derailing me back into the exact point I'm trying to make. For someone who has never read any Iron Man comics, and only seen the Iron Man movies, the story across all three is self-contained and almost entirely functional; the only glaring weak points being the unnecessary kid sidekick and the frustratingly vague epilogue. Stuff like making Killian the leader of AIM instead of a random third-string nobody, or removing Extremis's techno-organic interface aspect...yes, complaining about stuff like that is what I'd consider dogmatic.