gear to defend against or use the following skills? What affects its success rate when the skill is at 100%?

Kote/Kans
Blackjack
Thief poisons
dagger specs
for that matter, spear/mace/axe/etc specs

I know there must be something for I had a warrior (more than 10y ago) that would never fall to blackjack, but could get impaled with minor difficulty. It's old, yes, but more recently I've noticed some people that can never land an entwine (at least against a specific opponent) and others do it easily. So what gives?

P.S. I've been away from the game for quite some time, so kudos to the immstaff for the changes I've noticed so far. Cool areas, cool skills (healers lost ironskin?!?), classes changes (rangers, tweaks to conjies, etc). But now you gave me the problem of not knowing jack anymore :p