>>16053945...The fuck? Dialga has STAB Steel-type moves. Which Xerneas is weak to. Dialga also has base 120 Attack, and sometimes ran Iron Head in Gen V.
Deoxys has literally nothing new to hit Dialga with. Superpower/Focus Blast stop Time just as well as they have in the past, if not less so due to Fairy. Dialga isn't weak to Ghost and Dark, merely neutral, and I personally can't think of anything that doesn't hit Dialga harder with a Ground or Fighting move. Remember, Ghost and Dark have the weakest STABs of any type, and even Giratina's STAB Griseous Orb Shadow Force is only slightly stronger than, say, Earthquake, while being flat-out weaker than Draco Meteor. Yveltal's Aura-Boosted STAB Dark Pulse is also weaker than Focus Blast on Dialga.
So, Dialga lost two resistances it didn't really care about in exchange from being neutral to the new type, while Palkia picked up a new weakness and can no longer profit from permanent rain quite as easily.
