I like stormcrow. Derringer I fear needs a bit of a switch on the skills. I was a bit unimaginative when it came to defensive passive skills.

Shield wall would be an ability. 
Shield bash would be an ability.
I'm willing to let overpower be a passive but it will be changed to something like "hitting opponents with shield causes stagger. If a staggered opponent is hit with a shield, they are knocked prone instead" 
That work for you?