I think the suit makes the AI feel a bit dumber too just because you are like a god with it and the AI just can't handle you disappearing like a wizard.
Yeah, I think people are misunderstanding some of the AI problems. The game mechanics simply demand MUCH more from the AI than most games would ever have to consider. In regards to the stealth functions I'd say it's one of the most difficult things to balance. If you make it too difficult to "disappear" that function could become frustrating and useless the second you break stealth (leading to trial and error retries) while making it too easy results in AI that appears stupid. They didn't quite find the right balance but I really didn't think it was that awful.
I'm glad they went for slightly less aggressive AI than overly aggressive. Their original Far Cry AI was complete shit for that reason. You could be spotted half a mile from a village which would result in every active enemy on the map becoming aware of your position. It simply wasn't fun.
What they DO need to work on, I think, is individualizing enemy encounters a bit more. You should be able to break stealth without alerting the group at large. Now if the AI fires their weapon or makes a call on the radio, sure, the rest of the enemies should now be hunting you. However, if you are spotted, there should be an initial element of surprise or something that makes it feel as if you snuck up on them. I always thought Metal Gear handled this really well in that it made each enemy feel like an individual threat that you could deal with in a number of ways. If they spotted you there was still a chance of eliminating them before they call for help.
Most shooters simply don't have these circumstances to contend with. Crysis is neither a straight stealth game nor a full on shooter. They need their AI to handle the best of both worlds and everything in between in addition to coping with a super powered suit. It's a huge challenge I'm sure.
Which is why I wish they'd bring the CE3 version of the first Crysis to PC. It'd run so much better, and mods with that new lighting would be amazing.
On top of that I actually really liked the changes they made to the interface. It's more streamlined but doesn't sacrifice the functionality present in the original game. They did a really good job with the conversion.