The activated ability is great in most decks, but I think it shines even better in a Dragon deck since the individual cards are very powerful, as are the tribal synergies
Its admittedly not the greatest rate as it only kills small creatures, but the debuff acts as a combat trick that discourages larger creatures from getting in, plus picking off that Orcish Bowmasters might be essential
It's important to keep cards that will help you add gas to your tank, so try to hold onto cards like Lucky, Pongo, Tinker Bell, Strike a Good Match, Hypnotize, and Improvize when you see them
Master of Pearls, Thousand Winds, and even Ponyback Brigade left their mark on the format, but the hexproof on Mauler made this a beast of a card, especially when backed up with any number of combat tricks