I think modding in Servo is inevitable. We just need to spend enough time and thought on it (with help from you guys) on how to do it right.
I think it's pretty easy to see offline mode turning into "untrusted, cheat your butts off" mode eventually. We don't have any problem with that. If you were to go into that mode and play online, well, you're asking for crazy stuff to happen. But, that would allow you and your friend to play with mods.
We are uber protective of the sanctity for the 'trusted' multiplayer mode, of course. So, given that we're a pretty small studio, we've set mods aside for the moment because we simply can't do everything. Once the base game is done, we'll take stock of the feedback and start adding the most requested features.