Err... I didn't say that uncharted doesn't have cannon fodder FYI
And how could you not understand what I said? Buzzwords be damned, in a game you go through levels and shit happens. The shit that happens, especially in uncharted, IS the story. And in regards to my OP of this conversation, interactivity means, umm... controlling the character (drake) as a building falls, as spikes from the ceiling drop down on you, as you navigate your way up a train dangling on the side of a cliff. These are not cut scenes, you get to play them/have control of the character/are able to jump/run/shoot, etc. I don't know if your definition of interactivity is different but if it is, I don't give a shit. That has nothing to do with what I was responding too.
As for what these events add in terms of story/characterization, simply take portal 2 as a parallel to uncharted 2. In many cases, you're with another character (Glados/Wheatley), the same situation with Uncharted (Chloe, Elena). Shit happens, Glados/Elena or Wheatley/Chloe, say something, do something, react in some way shedding so light into who they are, how they act. Etc. Just look at the instance where Glados get's turned into a potato and you get to carry her, it, on your portal gun as she, it, insults you, directs you, boils with anger at Wheatley. It sheds some light into the character/entity that is Glados. Same with uncharted with the constant dialogue, constant action, constant character interaction (I'm sorry if that is too much of a buzzword for you) same as portal 2 and many other games for that matter. There's more than just shooting cannon fodder...
Have I made myself clear?