Something very fundamnetal is missing in modal logic:
The LOGIC OF POTENTIALITY!
Think of this:
"A horse is Potentially a unicorn"
The proximity of this is tighter than is of the Logic of Possibility. It's better than a mere possibility. Although this may be enhanced by preloading it with a domain or a boundary, but I think this is irrelevant. Perhaps this is better called 'TRANSITIONAL LOGIC' to widen its scope to also cover facts captured in transit from possibilty to necessity.