Does stomping count as "channeling"?
                                    Call me Smith.                                
                                
                            I believe so yes
It shouldn’t.
You can always test this in the mist though.
Pretty sure Quickness affects finishing moves, so it would make sense that it’s treated like a channeled ability.
Test it in the mists how?
                                    Call me Smith.                                
                                
                            You can test it against the combat NPCs in the mists
                                    The Shipwrecked Pirates
Tarnished Coast
                                
                            Tarnished Coast
Or you can stomp in the mists tutorial
                                    Arenanet: The paragon of truth.                                
                                
                            FYI I just tried it and it doesn’t appear to boost armor while stomping
                                    The Shipwrecked Pirates
Tarnished Coast
                                
                            Tarnished Coast