The danger of bringing grotsnik is not having the ability to choose which unit Snikrot would attack. The ideal use of ambush being to obliterate a high payout target and not simply attacking whatever is at hand or whatever you get screened with. And attaching Grazzy is risky because slow and purposeful could really backfire on you IE failing the assault because your move roll blew and staring at bad end of a termy squads crumpin range. Warbosses on bikes or just klaws seems a better use of both points and the kommandos.