Hm... sounds interesting. Sounds like there may be a way to make a "custom campaign" kinda thing then? Maybe even without the user having to download the maps, but instead just connecting to a "Custom Campaign Server" [i.e. a more advance/scripted version of the sandbox] And do you mean that the entire map is streamed to you via the server? This sounds like it might be a little troublesome for bots in the future due to them not knowing exactly which way will need to be taken [unless we find a way to intercept that streamed data and feed in some pre-recorded data without the server minding too much]. There will probably need to be alot of "roaming around" and following paths as well.
All those random stream-of-thought ideas are based off alot of assumptions, so they should be treated with a grain of salt. Just ideas.