I finally got my Vampire Hunter rebuilt with 6 fully-leveled Assassin talismans (3 Shield, 3 Barrier) and I loaded him up with 15 Skill Shards. Strike got maxed out at Level 6, so it's a good test case for its current effectiveness.
It's not effective.
Like, wow, it's not effective. "Wet noodle" comes to mind. Part of it is because it's only physical damage and not true damage or physical+magical. Part of it is because you only get a 30% bonus to damage from skill sharding - by comparison, Rainmaker's Fervor gets a 70% bonus on its true damage. Thankfully Strike is being replaced in July with Dusk. I'm definitely curious as to how the leveling for Dusk will work. Some increases to the %chance to get another turn would be nice, but I'd really like to see something beefier than 5/10/15% for the damage bonuses.
I'm also building an Armor Dog to work alongside Vampire Hunter. That RACCAR guy had a pretty fun team involving a Rainmaker and an Armor Dog, so I figured I'd try something similar with my Vampire Hunter. Should be ready to go this weekend.