Advanced meta features and logic/networking for iPhone games

I've been playing with the Free Unity package and am really really liking it so far. The amount I was doing with so little code was quite refreshing.

But I am wondering how much stuff is now hidden form me and hard to access. Things like downloading data files from a server for new levels or content, or cloud storage of player data. Or anything a bit more under the surface that's less about the game itself, but more about how the game plugs into the rest of the world. Or creating an easily expandable engine that can be extended without code/compilation level changes.

I realize I can create a Prefab for a weapon very easily, but I am assuming this stuff becomes hardcoded in the compiled game. I'm looking to have a more flexible engine that configures itself from datafiles, rather than hardcoded compiled values for hardcoded game object instances.

Creating a self contained game with this sort of visual development environment seems really powerful and agile. But does this make this sort of meta-logic more difficult?

Or can I manage game logic within Unity, and this meta layer in raw Objective-C manipulating data and behaviors read by Unity later? Not really sure what the path for this is, I just want to know it's possible before I veture far down this path. A technology that only does 90% of what you need and locks you out of the rest isn't going to work.

I hope all that makes sense, and I really hope I can dive feet first into Unity. Thanks!