Yeah, Mega Salamence looks kinda odd. Though he still has his front legs, they're just tucked in.
Salamence was a digimonesque take on the Western dragon, not very fond of it. The coolest dragonlike Pokémon is still Charizard in my book, despite not being Dragon-type, because the "Dragon" type is really a "dinosaur" type since dinosaurs are afraid of the cold.
Actually lizards are afraid of the cold as well, due to being cold blooded. Since dragon-types are typically less dinosaur and more 'giant, firebreathing lizard'...