I think my general thoughts are that it might be worth prioritizing part-related concepts discussed in the other thread (Multicellular Parts) - such as the digestive/signalling/nerve system analogues - over a more elaborate feature which we aren’t fully sure about.
Non-cell parts sound fun and open up a realm of possibilities - shields, unique abilities, etc. - but because they’re a pretty alien concept to Thrive as of now and would likely require a ton of design and manpower, we aren’t fully sure where that could lead, and if the time sunk into that would do a meaningful job of having an impact on larger questions for the multicellular stage.
I think more traditional parts also tie more conveniently into larger themes of progression - for example, having the presence of certain parts results in a more advanced start to the macroscopic, needing to implement certain internal parts/organelles before progression, etc. It’s a bit harder to tie non-cellular parts to progression in the same way.
So while non-cellular parts are a good idea to make the multicellular stage more fun, I’m not fully sure if they work as well as other concepts in filling out the needs our stage currently has.