Loading delays. The realtime resource pipeline isn't as fast as the prepackaged pipeline. But I don't think it's going to be much of an issue, especially if we cache common mods on your hard drive as UnityPackages.
Viewing post in The Galactic Line
The problem isn't really the download bandwidth, it's just the fact that you're loading stuff midgame. Like there's that little stutter when you walk out of a house in an FPS, because it has to load up a bunch of new textures? Or how you get low-res stuff for a bit before the high-res stuff loads? That's what we'd see.