No, it's still cracked. 100/120/120 bulk is fantastic, and 90 speed is decent; a bit slow for an offensive mon, but just fine for a bulky attacker.
The main problem is the offense. 150 SpA + a 20% boost to STAB moves + 130 BP Draco Meteor and 140 BP Steel Beam means you simply delete any neutral target not named Blissey - even Clodsire is 2HKO'd. Fighting (Aura Sphere, Focus Blast), Ground (Earth Power), Fire (Fire Blast, Flamethrower, Overheat), Ice (Ice Beam), and Electric (Thunderbolt) coverage means that, unlike some mons, Dialga isn't lacking for coverage options; as well, Flash Cannon and Dragon Pulse offer no-drawback options for STAB, too, in case you prefer a set that sticks around.
252 Atk Great Tusk Headlong Rush vs. 252 HP / 0 Def Dialga-Origin: 338-398 (83.6 - 98.5%) -- guaranteed 2HKO
Super effective, 120 BP STAB from Great Tusk and you're not even killing without hazards? That's just grotesque bulk, and Dialga-Origin is just a stat check mon that does, indeed, stat check OU.