>>20184758Blastiose gets 20 bp boost in attack, if you remove it from attack and split it even between defenses,you get 79/130/125.
And considering a water/steel typing and a bold nature, if it faces a lucario (regular, not mega), blastiose will receive a close combat, resulting in:
252+ Atk Life Orb Lucario Close Combat vs. 252 HP / 0+ Def Mega Blastoise: 361-429 (99.7 - 118.5%) -- 93.8% chance to OHKO
or
252+ Atk Life Orb Lucario Close Combat vs. 252 HP / 252+ Def Mega Blastoise: 299-354 (82.5 - 97.7%) -- guaranteed 2HKO
In both cases, Blastoise can OHKO with Aura Sphere.
It may sound nice a steel typing, but in a metagame where close combat and earthquake are so common, it might not be the best idea.