i heard that Dragon Rage is OP in Gen 1, so that's why the anime clips say "it's the pokemon's most powerful attack. when i was playing Pokemon Pearl and saw Gyarados for the first time i also saw Dragon Rage for the first time, it one shot my Monferno, my most powerful pokemon back then (i only played Pearl back then). as you said, an excellent move at the start of any game, the point i got to was the point were trainers had their pokemon in their 30s.