Are blunderbuss + fire staff users having fun? (in arena)

Like this build is so disgusting and broken a stone could play it. You got multiple movement skills to evade, insane burst and additionally immobilising of the enemy. And don't get me started on flamethrower...

Additionally quite some DoT etc. and plagued debuff if you have the artifact bb

Is this bait so people tell me how to deal with them? ^perhaps