Bruce was never dead though...it's been made clear several times that he was lost in time after being shot by Darkseid's Omega Sanction in the finale of Final Crisis. Superman actually has died and was gone maybe six or seven months?
Superman didn't actually die, he was just in a very deep coma that was mistaken for death and was artificially prolonged when he was entombed and deprived of the healing power of yellow sunlight.
Actually, the Kryptonian regeneration chamber he was placed in hastened
his revival. Yes, Superman would have revived eventually
if exposed to sunlight, but it wouldn't have been concentrated as it was in the regen chamber.
Connor was placed in the same chamber after Infinite Crisis
, and it took him a thousand years to regenerate, because his cells aren't fully Kryptonian. (See Legion of Three Worlds
Also, Blackest Night
makes it clear that, yes, Superman was dead. Not a coma.