How about a crafting mod that allows the user to combine all the power armors from both games into a single super one?
Of course to do that the character would need a maxed repair, science, INT, and etc. score
To get it you need the appropriate perk at the appropriate level which may get up to level 40 or 50 due to the end-game content level of the armor.
Or allow modifications to previously existing armor (Light, Medium, Heavy, Power Armor). An example would be adding a mod that decreases the weight of heavy armor.
How does this sound? Any ideas you guys can give me?