I thought this was a Windows file storage issue that caused the separation. We used to be able to store world files on any drive and it was moved to C:\ in A20ish I think. Windows mandates the location and TFP couldn't alter that from my understanding.
When you load 7d2d doesn't it load the mods at the same time?
They are not loaded at world creation/loading, or am I mistaken? If it's at launch, I don't think you could have them be world specific without a lot of code alteration.
For similar reasons I have my spawn.xml and biome.xmls saved in a world specific folders so I can swap them out as I like to make changes. I keep the OG in an OG XML folder so I can easily go back to vanilla.