LeoLancaster
does this still work
Tyrantrum's defensive typing is not deplorable, it quad resists Fire which makes it an excellent check to Entei when paired with a Heal Bell user, and it resists Flying which makes it an excellent Crobat check. Could it be better? Sure, but Tyrantrum is an offensive Pokemon, it doesn't need to have an great defensive typing to succeed.Tyrantrum to B:
Tyrantrum's advantages are weighed down by its several drawbacks.
These drawbacks include but are not limited to:
-Deplorable defensive typing
-Pitiful susceptibility to special attacks
-being outclassed by other wallbreakers
Other Pokemon such as Heracross or even Escavalier make for better wallbreakers, as their presence is more threatening due to their more threatening movepool, attack stats, as well as better offensive typings.
It's susceptibility to special attacks is a hurdle, but on the flipside it has a base Defense stat of 119, allowing it to, as mentioned before, check physical Fire- and Flying-types, and be somewhat difficult to force out by physical attackers. For example, Mega Aerodactyl's Earthquake does max 75%. Could it's defensive stats be better? Sure, but again, Tyrantrum is an offensive Pokemon, it's defensive capabilities are not the primary way it succeeds.
Finally, you're really underestimating the power of Choice Band Head Smash. It's literally bring a Rock resist or die. You don't need a deep movepool (although having coverage options such as Earthquake and Superpower, as well as a secondary STAB, is nice), a sky-high attack stat (although 121 is pretty great already), or great STAB coverage (even though Rock is usually enough by itself) when you 2HKO Cresselia with a neutral hit. And to top it all off, you can patch up that mediocre Speed stat with Rock Polish, and still 2HKO Cress and Suicune with just a bit of chip damage and a Life Orb.
Obviously Tyrantrum does have it's flaws, such as it's low Speed and, as you said, poor Special Defense, but you're overvaluing these flaws and ignoring the sheer spammability and power of Head Smash.