I'm fine with moving Bennett for the right price, but I don't think this is a good return for him. Armia and Roslovic are complimentary pieces at best: I think Armia's odds of becoming a legit second-line winger are about the same as Bennett's of becoming a legit first-line winger. Roslovic I'm likewise not sold on, I haven't followed him much since his draft year but if he's not actively making me pay attention like some recent draftees have, I don't think he's a good enough piece to include in a deal for a potential core piece. Chiarot is a nice throw-in, I think he's on the cusp of becoming a great #5, but it's not like we're hurting for defensemen.
Basically the way I think the deal breaks down is we give up a guy who has the potential to be one of the team's best players for guys who best case scenario end up being about as good as Frolik is now. If we were to trade Bennett I would want at least a guy who has the same sort of game-breaking potential.