really? I never read a bunch of spoilers at all nor am I saying you do ethier but the marketing, trailers etc all showed whiplash as the main villian. "come to burger king and try the whiplash whopper", "come to 7 eleven and get you orange whiplash slurpee".
Im saying though he was marketed as the main villian in ironman 2 and they didnt deliver on that contrary to what many will defend. If your going to go that route of marketing whiplash to be the main guy then make it that, dont shoe horn another guy in and make him do all the sutff that whiplash could of done.
No I dont expect to see how they were born but by no means were these chracters fully fleshed out. now the approach Im going to lay out is someone who has not read a single comic but likes the movies.
Nick fury - who is he and what does he do at shield? (never answered)
Shield - we still dont know what they do after two movies
Black widow - what did she really do in this movie? no backstory given. you could of taken her out of the movie and it wouldnt have changed a thing.
Justin hammer - what was his motivation? government contracts? stark dead? no backstory ethier given. you see when a character has a motivation for the audience to understand and believe then it makes something called "tension" more believable.
Whiplash - they kinda did a backstory here with his dad and starks dad but the plot hole here is why did they send them back to russia to apply there knowledge to russian technology?
First of all, Jon Favreau isn't responsible who gets put in a Whopper or a Slurpee.
Second, it's easier to sell a Whopper with Whiplash on it rather than a guy in a business suit.
Maybe you should pay more attention to the movies and not look for stuff to nit pick.
Nick Fury - at the end of the first movie he said "I'm Nick Fury, Director if SHIELD, I'm here to talk to you about the Avenger Initiative."
SHIELD - Pepper and Coulson had this convo
Coulson: I'm agent Phil Coulson, with the Strategic Homeland Intervention Enforcement and Logistics Division
(now if you didn't already realize he was part of the Government especially when he said
Homeland Intervention he then said this)
Pepper: You know we've been approached by the DOD, the FBI, the CIA...
Coulson: We're a separate division, with a more specific focus.
Seems to me like you need things spoon fed to you, how many movies have gone into great detail about what those divisions do? Did people need a 15 minute explanation in Mission Impossible about the CIA? NO, you know why because most people are smart enough to understand what the CIA is and what they do.
Black widow -

She was put there by Nick Fury to spy on him. If she wasn't there she would've never told Fury about Stark's condition and Stark would've never gotten his dad's case. She was also responsible for getting control of War Machine.
Justin hammer - pretty obvious, he wanted to take Stark's place as the military's top go to guy. Did people need a back story on where Eddie Brock came from and why he wanted to take Parker's job? Did anyone need a back story on where Dent came from and why he became the new DA? Did people need a back story on where Stryker came from in X2? And Stryker was really the main villain in X2, why didn't he get his own Slurpee cup, while the others did?
Whiplash - Kinda did a backstory? gtfo, he had the most back story out of most of the other people. Why did they get sent to Russia? His dad got caught trying to sell technology illegally got sent to Siberia.
These movies need to be like pop up video for some people, someone shows up and next to them a bubble with text in it should appear explaining who they are.