This is an adaptation of an idea I have already suggested and has also been suggested by others.
Individual modules, OSC, Filt, LFO...
Here's where Thor comes in: You have already split Thor in to modules now just go one step further and allow them to be loaded individually as self contained units. Keep the original Thor as it is, but have this as well "Thor construction blocks"
If you wanted to take it a step further you could also have a Thor "shell" like combinator which has the modulation section built in, but make it so that anything can be loaded in, a Thor combinator hybrid.