I know Dark Heresy has not the best rules set all around (still a great game though) but the unarmed and grapple rules are an absolute nightmare!
First of all, unarmed strikes my not be parried or dodged. See below. So if I am armed with a power sword, and someone punches me all I can do is roll agility to get out of the way…
According to the core rules (pg. 197 and pg.190) a grapple may be initiated with an unarmed attack or a charge. And now the carnival begins!
The defender may not dodge. The defender can spend a reaction and roll Agility to avoid the attack but not use the dodge skill.
A grappled character may only take the grapple action. That means, either opposed strength checks, or a contortionist skill check to escape the grapple. No attacks with small weapons like knifes, no reload, No psychic tricks. A player even thought of unpinning a grenade and let it fall at his feet but NO.
So, any thoughts on how we can fix this mess ?