From my limited vantage point I can see little reason why we couldn't get tuning mod capability like being able to edit weapon/vehicle variables. While the complex licensing agreements revolving around the various software and dependencies the game uses would prevent things like map editors and custom models, it's hard to see why a tuning mod kit like the one for Company of Heroes series for example couldn't be made for Frostbite. In fact, they already do for past games in the form of 3rd party tools that I will not mention here.
Tuning mods would be an natural extension for Portal. Yes it falls well short of full on modding but it would open up a huge world with which to play with all the variables and create balance mods, sim mods and more.