The nanosuit 2 is not simply an augmentation suit like nanosuit 1. It has two main layers and contains synthetic nanoweave material that can interact with organic compounds under the outer shell (i.e. the deep layer). My own theory on why it looks bulkier than nanosuit 1 is due to this second layer. This deep layer performs processing of viral DNA as well as the DNA of the wearer, as opposed to nanosuit 1's ability to access bodily functions but has no processing capacity. To allow for this processing, a massively powerful onboard computer is present and loaded with an AI that monitors and controls the whole suit's functions. Due to the "symbiotic" relationship (as the suit has full access to the wearer's body) the AI appears to mimic the personality of the wearer over time.
Such processing is the storyline's key point of why the suit is so important. Its capability to process alien tissue has been engineered by Hargreave for over 100 years; no one else has comparable knowledge (maybe except for his friend Karl). As such, the suit plays a key role in fabricating a counter-virus to the alien's viral spores.
Interesting note: some people seemed to think that Helena Rosenthal invented a "cure" in Crysis 1. That is not the case. What she found out was the frequency the alien's exosuits used to communicate and used that same frequency to upload a computer virus (not biological!) to shut down the exosuits. How she figured out the alien's computing technology I'll never know (it most likely wouldn't be digital!). Engineering such a virus also requires knowledge of the code of the target system... It's impossible for anyone to come up with that from the time Nomad got on board the carrier to the time the virus was put to use. It's just a game, right?
At the start of Crysis 2 CELL personnel were shooting you because they thought you were Prophet. As you know, Prophet was infected and by moving around he was spreading the virus. CELL's job was to contain the infection and thus Prophet. Prophet did not cooperate after Hargreave's deception and worked with Gould instead to come up with a cure. Honestly, I don't think a person like Gould would be able to come up with a cure to this even if he had a 100 years more.
Normally Alcatraz would have died but the nanosuit 2's symbiotic capability was what sustained him; it grew into his wounds and supported his body. This was the reason why when he was captured they could not simply remove the suit; they had to bring him to a skinning lab. Prophet was not in such condition when he put on the suit thus the suit did not grow into him, allowing him to remove it at will. Alcatraz was royally screwed huh :p
Wearers of the nanosuit 1 would have died if they got exposed to the viral spores. Nanosuit 2's deep layer processing ability was what saved Alcatraz. The very first time Alcatraz got exposed he 'died' but the suit isolated the virus from his body (quoting the suit "corrosive agents isolated") then revived him with a defibrillator (press space to shock the heart!). On a side note, Prophet actually discovered the main spore disperal tower under Central Park before the game started; he knew what was up but he didn't have the cure with him at the time and was why he was so desperate that he worked with a fool like Gould. The spores were not released yet though, so the suit never experienced the spores before. After Alcatraz's first encounter with it, the suit was immune to the spores from that point forward.
Tara Strickland was a pretty amazing woman. 3 years before the game started (when her father died) she went into a 'depression' and started drinking heavily and took drugs. She got a dishonourable discharge from the Navy SEAL. It was revealed in-game that she is actually a CIA agent. My theory is this: she was recruited into the CIA 3 years ago from the Navy SEAL (she was apparently the best). In order to keep this secret she purposefully staged her dishonourable discharge and after that recovered from all the drugs and alcohol. Another cool CIA stuff.
Fast forward to the revelation of Hargreave's popsicle state, he mentioned that his colleague Karl Earnst Rasch (not sure on spelling) did not follow in his path of 'immortality' and Hargreave assumed Karl was long dead. However, by the end of the game after Alcatraz climbed up a pile of rubble there was an incoming transmission. You all remembered that one didn't you? The one where Alcatraz said "They call me... Prophet". Well before that line the person said "Karl Earnst Rasch, at your service. And you are?". Am I the only one surprised by that line?
Happy gaming.
tl;dr? Don't bother commenting please.