Breaking out of pins is ridiculously difficult, and needs a tweak.

[Frank_Stein]

Here's an idea: what if either one or both hands could be used? One hand, you can wail on them but it's easier to break out of. Both hands and it's real hard to break out of, but obviously you can't do much either.

I think you could do something like that where, if the person is in a two handed pin they could resist at stamina cost to force a one handed grab, then resist again to knock the person off of them.

The person maintaining the pin could advance it again to keep them still. Depending on how much stamina is needed, you could have them need to wait again for it to rebuild to try again just slightly longer than it takes to reestablish the two handed pin