I think we should rescue instinctual variants from the enneagram and incorporate them into socionics because they make a lot of sense and would help sort out a lot of problems arising from intratype differences. If socionics describes how we perceive and modify the world around us, understanding socionics in light of instinctual variants would clarify how people allocate this 'perceiving' and 'modifying' energy.
This would also help prevent people trying to apply socionics from falling back onto stereotypes. For instance, an sp/sx ESE or an so/sx ILI would display the function order of their respective types, but neither would be a caricature of the stereotypical ESE or ILI.
Similarly, understanding how leading Te sx/sp manifests differently from leading Te so/sx (for example) would lead to a clearer understanding of different ways the same function can manifest in terms of the way different people allocate their energy, and it would make typing much easier.
I'll elaborate on the details of this later, but I think this would be a lot more helpful than a lot of the current subtype systems. Thoughts?