This is a smaller idea and it’s probably been suggested or codified somewhere on the dev/community forums, but I think it’s worth it to write it down here.
Thinking of things like migration (for food or for breeding), reproductive strategies, growth, lifespan, etc. that could make for very interesting gameplay in the Aware and Late Multi-Cellular Stage, I believe there should be an option to reproduce without entering the editor part of Thrive. Since each trip to the editor represents an evolutionary jump, each trip also represents an appropriate temporal jump forwards in time as well. And as we all know, evolution as a process will often take millions of years at minimum to create significant difference.
Considering this, I think it would be pretty difficult to fit things that could be very interesting features of Thrive, such as the above listed natural phenomena in the current and traditional “reproduce = evolution” mechanic we have in now. In those millions of years between evolutionary jumps, landmasses move, oceans form, climate changes, and the lifeforms around you either disappear or are altered. How can you experience the entirety of a coherent and consistent migration pattern you set up - going to that area, reproducing, then going back to your original landmass - if you jump forward a thousand generations every time you breed? What guarantee is there that the landmass you migrate to will even look the same or be there with the rise and fall of sea level, or what’s stopping that local environment from becoming much less hospitable to the youth in your species? Allowing the player to reproduce without jumping forward a million years can also solidify the impact of other aspects of editing your creature - lifespan, reproductive strategies, etc. don’t mean much if the life of your organism after it reproduces is skipped.
Of course, being able to reproduce and not evolve immediately means a lot more work, since it means no shortcuts in those more complex animal behaviors that must be simulated. But after a certain point of development where enough gameplay is present to make Thrive a deep and engaging experience, I think allowing this feature would benefit replayability and fun.