I always disliked grabs becuase they were so hard to get rid of. An opponent that got a good grab has insane control and when you are in that position there is not too much you can do (atleast from my experience)
Due to this I suggest a pain meter. Somewhere above your tori you have a meter that gets filled up each time your tori takes severe damage. When your meter is filled up your tori will slightly stagger, letting go of both grabs and maybe relaxing some other part of the body. Blows to the head would make the meter fill up the fastest. Hits to the lumbar / abs will also do a lot of damage since the liver and ribs are located there (I think, was never good in biology xD)
Not only do I believe this makes the game more interesting but it also makes one of my favorite things to do more viable, punching. A strong punch to the head could probably fill up the meter instantly making a previously unseen strategy be more viable (atleast in aikido)
Anyways let me know what you guys think of this idea, this meter does not have to be universal, maybe just for a few mods?