Pankration (or, modern, pancration or pancrase) was and is very effective. However, it is less a style in and of itself and more a collection of techniques & limitations (or rules). Not so much a self-contained system (like judo or shotokan karate)...think more general, like the term MMA (mixed martial arts). MMA is not itself a style, but a collection of techniques used within a set of limitation (rules).
As I've mentioned in the past here, I used to fight pancrase events years ago. As with events like UFC & Pride, people of various styles & backgrounds stepped into the ring, but they fight within a set of rules (no pulling hair, for example, or intentional groin shots).
But back to the original question:
Again, the tone of the fight is always set by WHY the fight is happening. Why the fight is happening will tend to dictate methods used.
For example, if two combatants are going head to head in single combat over the favors of a female, there will be lots of posturing & such. The fight could be mostly fisticuffs, or it may well go to the ground, where it can stay until there is a clear victor. Lethal techniques employed to their ultimate end are less likely (& less needed).
If one is being stalked & confronted by a group of thugs (say a lone hunter has inadvertently stumbled within the grounds of an unfriendly tribe), using ground techniques is hardly the best option, as there is no guarantee of single combat. It could easily be 2 or 3 or 4 against one, & being on your back in such a situation is asking for trouble. In such a case, quick strikes with rapid footwork is a better strategy while looking for an escape!
As to how developed their arsenal of techniques was - depends on when & where & who. Sapiens were more advanced than others, and with it probably had a better set of techniques. Later sapiens probably had a much more comprehensive tool-box, as we can teach & pass information down the line.
