Was it explained? I can't remember, was Thor that big a Threat to the universe?
well since this is the Battle board
Warrior Madness Thor vs Doomsday
vs Cyclops's Extinction team
vs The Masters of Evil
vs Brotherhood of Evil Mutants
No, power gem Thor wasn't a universal threat.
As for the match ups, Warrior Madness Thor loses them all. Warrior's Madness would rob an Asgardian of his wits, reducing him to a mindless powerhouse. He'd probably just run around smashing things and we both know how useless a character like that would be.