Yep. You heard me. I'm questioning you comparing AShinmyoumaru to Garchomp.
Now, I'm not saying AShinmyoumaru is not a threat. It is... just not like Garchomp is. Let's break this down.
AShinmyoumaru's reliable STAB options are Body Slam and Draw the Line. Garchomp's reliable STAB options are Dragon Claw and Earthquake. Draw the Line's criticals are nice and all, and Shinmyoumaru gets Earthquake by TM, but that's pretty much eclipsed by STAB Earthquake from chomp.
Next, onto type. Garchomp might not have as many resistances as AShinmyoumaru, but it also has two less weaknesses (one, if you include Fairy). Also, one of its resistances is to Rock, including the famed
Sneaky pebbles Stealth Rocks. AShinmyoumaru's immunity is to Miasma, which, no, no matter how badly you try to buff it, Poison immunity is still borderline worthless (BORDERLINE due to Toxic, but remember AShinmyomaru's ability?). Garchomp, on the other hand, gets an immunity to Electric - still not optimal, but hey, it's KIND OF a thing.
Still on the topic of type, their weaknesses. Garchomp is weak to Dragon, Ice(x2), and Fairy - the last of which didn't even exist when it was banned. AShinmyoumaru is weak to Dream(2x), Earth, Faith, and Fire. Earth and Dream both have some of the most outstanding moves in the game (Earthquake and High Jump Kick). STAB Ice is few and far between, Dragon is a mutual weakness in all cases (most by Dragon Claw, and Dialga by Earthquake), and Gen 4 and 5 didn't believe in fairies.
Now, out of the area of total 'Chomp dominance. Abilities! Garchomp gets Sand Veil - boosting evasion by 20% in sand. Keep in mind, back then, ability-induced weather lasted until it was replaced. AShinmyoumaru gets Guts, boosting Attack by 50% in bad status. It's a bigger and more reliable boost, but Garchomp isn't taking damage the whole time. Still most likely the first victory to the Inchling of Attack.
And then, their stats. AShinmyoumaru has Attack and Speed of 140/120, while Garchomp has the same stats as 130/102. Seems like a win for AShinmyoumaru, right? Well, then you look at their bulk. For that offense, 55/110/70 looks good, right? Garchomp's incredible 108/95/85 begs to differ.
...So, if you want offense, AShinmyoumaru is the bigger threat, but Garchomp's versatility takes the cake here.
