Use of V/S.... yes that's true. But that by itself does not constitute a "safety concern" as the title of this thread suggests, or such statements as "Climb out showed a constant struggle of flight deck with engine controls, drove the plane like a Chinese cab driver from full power to idle to full power."
It does however indicate un-polished flying, lack of "refinement" perhaps, assuming multiple low level step climbs were indeed the reason for Fendant's experience.
As to cabin crew attitude, agree wholeheartedly.