I'm just trying to wrap my head around how some of the keyword stuff works. Would this feat give you combat advantage against someone so long as you wielded a frost weapon (doing cold damage)?
It works. You'll want to add Lasting Frost to the mix to make sure they've got Cold Vulnerability, and do an extra 5 damage every time you hit for two turns in a row.
However, it's a fairly feat-intensive way of getting +2 to hit and possibly sneak attack. Skill Focus: Stealth and a friend to flank with will likely be just as effective in granting you a steady stream of turns with Combat Advantage.
